Scrigroup - Documente si articole

Username / Parola inexistente      

Home Documente Upload Resurse Alte limbi doc  


AccessAdobe photoshopAlgoritmiAutocadBaze de dateCC sharp
CalculatoareCorel drawDot netExcelFox proFrontpageHardware
HtmlInternetJavaLinuxMatlabMs dosPascal
PhpPower pointRetele calculatoareSqlTutorialsWebdesignWindows
WordXml

AspAutocadCDot netExcelFox proHtmlJava
LinuxMathcadPhotoshopPhpSqlVisual studioWindowsXml

Producing Consistent Color

photoshop

+ Font mai mare | - Font mai mic



DOCUMENTE SIMILARE

Trimite pe Messenger
Pixelate filters
Selecting and modifying slices
Sharpen filters
About drawing and painting
Changing the size of the work canvas
Video filters
Mixing color channels (Photoshop)
Setting options for Chinese, Japanese, and Korean type
Converting between paths and selection borders
Using the paint bucket tool


Producing Consistent Color




(Photoshop)

Why colors sometimes don’t match

No device in a publishing system is capable of reproducing the full range of colors viewable to the human eye. Each device operates within a specific color space, which can produce a certain range, or gamut, of colors.

The RGB (red, green, blue) and CMYK (cyan, magenta, yellow, black) color modes represent two main categories of color spaces. The gamuts of the RGB and CMYK spaces are very different; while the RGB gamut is generally larger (that is, capable of representing more colors) than CMYK, some CMYK colors still fall outside the RGB gamut. (See “Color gamuts

(Photoshop)” on section 91 for an illustration.) In addition, different devices produce slightly different gamuts within the same color mode. For example, a variety of RGB spaces can exist among scanners and monitors, and a variety of CMYK spaces can exist among printing presses.

Because of these varying color spaces, colors can shift in appearance as you transfer documents between different devices. Color variations can result from different image sources (scanners and software produce art using different color spaces), differences in the way software applications define color, differences in print media (newsprint paper reproduces a smaller gamut than magazine-quality paper), and other natural variations, such as manufacturing differences in monitors or monitor age.

About color management

Because color-matching problems result from various devices and software that use different color spaces, one solution is to have a system that interprets and translates color accurately between devices. A color management system (CMS) compares the color space in which a color was created to the color space in which the same color will be output, and makes the necessary adjustments to represent the color as consistently as possible among different devices.

Note: Don’t confuse color management with color adjustment or color correction. A CMS won’t correct an image that was saved with tonal or color balance problems. It provides an environment where you can evaluate images reliably in the context of your final output.

Photoshop follows a color management workflow based on conventions developed by the International Color Consortium (ICC). The following elements and concepts are integral to such a color-managed workflow.


Color management engine   Different companies have developed various ways to manage color. To provide you with a choice, a color management system lets you choose a color management engine that represents the approach you want to use. Sometimes called the color management module (CMM), the color management engine is the part of the CMS that does the work of reading and translating colors between different color spaces. Color numbers   Each pixel in an image document has a set of color numbers that describe the pixel’s location in a particular color mode—for example, red, green, and blue values for the RGB mode. However, the actual appearance of the pixel may vary when output or displayed on different devices, because each device has a particular way of translating the raw numbers into visual color. (See “Why colors sometimes don’t match” on section 102.) When you apply color and tonal adjustments or convert a document to a different color space, you are changing the document’s color numbers.

Color profiles   An ICC workflow uses color profiles to determine how color numbers in a document translate to actual color appearances. A profile systematically describes how color numbers map to a particular color space, usually that of a device such as a scanner, printer, or monitor. By associating, or tagging, a document with a color profile, you provide a definition of actual color appearances in the document; changing the associated profile changes the color appearances. (For information on displaying the current profile name in the status bar, see “Displaying file and image information” on section 48.) Documents without associated profiles are known as untagged and contain only raw color numbers. When working with untagged documents, Photoshop uses the current working space profile to display and edit colors. (See “About working spaces” on section 106.)

Do you need color management?

Use the following guidelines to determine whether or not you need to use color management:

•     You might not need color management if your production process is tightly controlled for one medium only, for example, if you’re using a closed system where all devices are calibrated to the same specifications. You or your prepress service provider may prefer to tailor CMYK images and specify color values for a known, specific set of printing conditions.

•     You also might not need color management if you are producing images for the Web or other screen-based output, since you cannot control the color management settings of monitors displaying your final output. It is helpful, however, to use the Web Graphics Defaults setting when preparing such images, because this setting reflects the average RGB space of many monitors. (See “Using predefined color management settings” on section 105.)

•     You can benefit from color management if you have more variables in your production process (for example, if you’re using an open system with multiple platforms and multiple devices from different manufacturers). Color management is recommended if you anticipate reusing color graphics for print and online media, if you manage multiple workstations, or if you plan to print to different domestic and international presses. If you decide to use color management, consult with your production partners—such as graphic artists and prepress service providers—to ensure that all aspects of your color management workflow integrate seamlessly with theirs.


Creating a viewing environment for color management Your work environment influences how you see color on your monitor and on printed output. For best results, control the colors and light in your work environment by doing the following:

•     View your documents in an environment that provides a consistent light level and color temperature. For example, the color characteristics of sunlight change throughout the day and alter the way colors appear on your screen, so keep shades closed or work in a windowless room. To eliminate the blue-green cast from fluorescent lighting, consider installing D50 (5000 degree Kelvin) lighting. Ideally, view printed documents using a D50 lightbox or using the ANSI PH2.30 viewing standard for graphic arts.

•     View your document in a room with neutral-colored walls and ceiling. A room’s color can affect the perception of both monitor color and printed color. The best color for a viewing room is polychromatic gray. Also, the color of your clothing reflecting off the glass of your monitor may affect the appearance of colors on-screen.

•     Match the light intensity in the room or variable lightbox to the light intensity of your monitor. View continuous-tone art, printed output, and images on-screen under the same intensity of light.

•     Remove colorful background and user-interface patterns on your monitor desktop. Busy or bright patterns surrounding a document interfere with accurate color perception. Set your desktop to display neutral grays only.

•     View document proofs in the real-world conditions under which your audience will see the final piece. For example, you might want to see how a housewares catalog looks under the incandescent lightbulbs used in homes, or view an office furniture catalog under the fluorescent lighting used in offices. However, always make final color judgments under the lighting conditions specified by the legal requirements for contract proofs in your country.

Setting up color management

Photoshop simplifies the task of setting up a color-managed workflow by gathering most color management controls in a single Color Settings dialog box. You can choose from a list of predefined color management settings, or you can adjust the controls manually to create your own custom settings. You can even save customized settings to share them with other users and other Adobe applications, such as Illustrator 9.0, that use the Color Settings dialog box.

Photoshop also uses color management policies, which determine how to handle color data that does not immediately match your current color management workflow. Policies provide guidelines on what to do when you open a document or import color data into an active document.


To specify color management settings:

1   Do one of the following:

•     In Windows and Mac OS 9.x, choose Edit > Color Settings.

•     In Mac OS X, choose Photoshop > Color Settings.

To display helpful descriptions of the options that appear in the dialog box, position the pointer over a section heading or menu item. These descriptions appear in the

lower area of the dialog box.

2   Do one of the following:

•     To set up a predefined color management workflow, see “Using predefined color management settings” on section 105.

•     To customize your own color management settings, see “Customizing color management settings” on section 107.

Using predefined color management settings

Photoshop offers a collection of predefined color management settings designed to produce consistent color for a common publishing workflow, such as preparation for Web or offset press output. In most cases, the predefined settings will provide sufficient color management for your needs. These settings can also serve as starting points for custom- izing your own workflow-specific settings.

To choose a predefined color management setting, choose one of the following options from the Settings menu in the Color Settings dialog box.

Color Management Off   Uses passive color management techniques to emulate the behavior of applications that do not support color management. Although working space profiles are considered when converting colors between color spaces, Color Management Off does not tag documents with profiles. Use this option for content that will be output on video or as on-screen presentations; do not use this option if you work mostly with documents that are tagged with color profiles.

ColorSync Workflow (Mac OS only)   Manages color using the ColorSync CMS with the profiles chosen in the ColorSync control panel. Use this option if you want to use color management with a mix of Adobe and non-Adobe applications. This color management configuration is not recognized by Windows systems, or by versions of ColorSync earlier than 3.0.

Emulate Photoshop 4   Emulates the color workflow used by the Mac OS version of

Adobe Photoshop 4.0 and earlier.

Europe Prepress Defaults   Manages color for content that will be output under common press conditions in Europe.

Japan Prepress Defaults   Manages color for content that will be output under common press conditions in Japan.

Photoshop 5 Default Spaces   Preparation of content using the default working spaces from Photoshop 5.

U.S. Prepress Defaults   Manages color for content that will be output under common press conditions in the U.S.


Web Graphics Defaults   Manages color for content that will be published on the World

Wide Web.

When you choose a predefined configuration, the Color Settings dialog box updates to display the specific color management settings associated with the configuration. About working spaces

Among other options, predefined color management settings specify the color profiles to be associated with the RGB, CMYK, and Grayscale color modes. The settings also specify the color profile for spot colors in a document. Central to the color management workflow, these profiles are known as working spaces. The working spaces specified by predefined settings represent the color profiles that will produce the best color fidelity for several common output conditions. For example, the U.S. Prepress Defaults setting uses a CMYK working space that is designed to preserve color consistency under standard Specifica- tions for Web Offset Publications (SWOP) press conditions.

A working space acts as the color profile for untagged documents and newly created documents that use the associated color mode. For example, if Adobe RGB (1998) is the current RGB working space, each new RGB document that you create will use colors within the Adobe RGB (1998) color space. Working spaces also define the destination color space of documents converted to RGB, CMYK, or Grayscale color mode.

About color management policies

When you specify a predefined color management setting, Photoshop sets up a color management workflow that will be used as the standard for all documents and color data that you open or import. For a newly created document, the color workflow operates relatively seamlessly: the document uses the working space profile associated with its color mode for creating and editing colors.

However, it is common to encounter the following exceptions to your color-managed workflow:

•     You might open a document or import color data (for example, by copying and pasting or dragging and dropping) from a document that is not tagged with a profile. This is often the case when you open a document created in an application that either does not support color management or has color management turned off.

•     You might open a document or import color data from a document that is tagged with a profile different from the current working space. This may be the case when you open a document that has been created using different color management settings, or a document that has been scanned and tagged with a scanner profile.

In either case, Photoshop must decide how to handle the color data in the document. A color management policy looks for the color profile associated with an opened document or imported color data, and compares the profile (or lack of profile) with the current working space to make default color management decisions. If the profile is missing or does not match the working space, Photoshop displays a message that

indicates the default action for the policy. In many cases you will also be provided with the opportunity to choose another action. For detailed information on the color management decisions associated with different policies, see “Specifying color management policies” on section 108.


Working with policy warnings and messages

The predefined color management workflows are set to display warning or option messages when a default color management policy is about to be used. Although you can disable the repeated display of some warnings and messages by selecting the Don’t Show Again option, it is highly recommended that you continue to display all policy messages, to ensure the appropriate color management of documents on a case-by-case basis.

(See “Resetting all warning dialogs” on section 56.) You should only turn off message displays if you are very confident that you understand the default policy decision and are willing to accept it for all documents that you open. You cannot undo the results of a default policy decision once a document has been saved.

Customizing color management settings

Although the predefined settings should provide sufficient color management for many publishing workflows, you may sometimes want to customize individual options in a configuration. For example, you might want to change the CMYK working space to a profile that matches the proofing system used by your printer or your service bureau.

It’s important to save your custom configurations so that you can reuse and share them with other users and Adobe applications that use the same color management workflows. The color management settings that you customize in the Color Settings dialog box are contained in an associated preferences file called Color Settings.

Note: The default location of the Color Settings file varies by operating system; use your operating system’s Find command to locate this file.

To customize color management settings:

1   Do one of the following:

•     In Windows and Mac OS 9.x, choose Edit > Color Settings.

•     In Mac OS X, choose Photoshop > Color Settings.

2   To use a preset color management configuration as the starting point for your customi- zation, choose that configuration from the Settings menu.

3   Specify the desired color settings (working spaces and policies). As you make adjust- ments, the Settings menu option changes to Custom by default.

For detailed customization instructions, see “Specifying working spaces” on section 107,

“Specifying color management policies” on section 108, and “Customizing advanced color management settings” on section 110.

4   Save your custom configuration so that it can be reused. (See “Saving and loading color management settings” on section 112.)

Specifying working spaces

In a color-managed workflow, each color mode must have a working space profile associated with it. (See “About working spaces” on section 106.) Photoshop ships with a standard set of color profiles that have been recommended and tested by Adobe Systems for most color management workflows. By default, only these profiles appear in the working space menus.

          


To display additional color profiles that you have customized or installed on your system, select Advanced Mode in the Color Settings dialog box. To appear in a working space menu, a color profile must be bidirectional, that is, contain specifications for translating both into and out of color spaces. You can also create a custom RGB, CMYK, Grayscale, or Spot working space profile to describe the color space of a particular output or display device. (See “Creating custom RGB profiles” on section 120, “Creating custom CMYK profiles” on section 121, and “Creating custom grayscale and spot-color profiles” on section 125.)

For information about a specified RGB or CMYK working space profile, see the Description area of the Color Settings dialog box. (See “Setting up color management” on section 104.) The following information can help you specify an appropriate Gray or Spot working space:

•     For images that will be printed, you can specify a Gray or Spot working space profile that is based on the characteristics of a particular dot gain. Dot gain occurs when a printer’s halftone dots change as the ink spreads and is absorbed by paper. Photoshop calculates dot gain as the amount by which the expected dot increases or decreases. For example, a 50% halftone screen may produce an actual density of 60% on the printed page, exhibiting a dot gain of 10%. The Dot Gain 10% option represents the color space that reflects the grayscale characteristics of this particular dot gain.

 

Proof (no dot gain), and printed image (with dot gain)

•     For images that will be used online or in video, you can also specify a Gray working space profile that is based on the characteristics of particular gamma. A monitor’s gamma setting determines the brightness of midtones displayed by the monitor. Gray Gamma 1.8 matches the default grayscale display of Mac OS computers and is also the default grayscale space for Photoshop 4.0 and earlier. Gray Gamma 2.2 matches the default grayscale display of Windows computers.

Specifying color management policies

Each predefined color management configuration sets up a color management policy for the RGB, CMYK, and Grayscale color modes and displays warning messages to let you override the default policy behavior on a case-by-case basis. If desired, you can change the default policy behavior to reflect a color management workflow that you use more often. For more information on policies, see “About color management policies” on section 106.

To customize color management policies:

1   In the Color Settings dialog box, under Color Management Policies, choose one of the following to set the default color management policy for each color mode:

•     Off if you do not want to color-manage new, imported, or opened color data.


•     Preserve Embedded Profiles if you anticipate working with a mix of color-managed and non-color-managed documents, or with documents that use different profiles within the same color mode.



•     Convert to Working Space if you want to force all documents to use the current working space.

For detailed descriptions of the default behaviors associated with each policy option, see the table following this procedure.

2   For Profile Mismatches, select either, both, or neither of the following:

•     Ask When Opening to display a message whenever you open a document tagged with a profile other than the current working space. You will be given the option to override the policy’s default behavior.

•     Ask When Pasting to display a message whenever color profile mismatches occur as colors are imported into a document (via pasting, drag-and-drop, placing, and so on). You will be given the option to override the policy’s default behavior.

The availability of options for Profile Mismatches depends on which policies have been specified.

3   For Missing Profiles, select Ask When Opening to display a message whenever you open an untagged document. You will be given the option to override the policy’s default behavior.

The availability of options for Missing Profiles depends on which policies have been specified.

It is strongly recommended that you keep the Ask When Opening and Ask When Pasting options selected.

Policy option                               Default color management behavior

Off                                                   •   New documents and existing untagged documents remain untagged.

•   Existing documents tagged with a profile other than the current working space become untagged.

•   Existing documents tagged with the current working space profile remain tagged.

•   For color data imported into a document using the same color mode, color numbers are preserved.

•   For all other import cases, colors are converted to the document’s color space.


Policy option                               Default color management behavior


Preserve Embedded

Profiles


•   New documents are tagged with the current working space profile.

•   Existing documents tagged with a profile other than the current working space remain tagged with the original embedded profile.

•   Existing untagged documents use the current working space for editing but remain untagged.

•   For color data imported within the same color mode between either a non-color-managed source or destination, or from a CMYK document into a CMYK document, color numbers are preserved.

•   For all other import cases, colors are converted to the document’s color space.


Convert to Working Space      •   New documents are tagged with the current working space profile.

•   Existing documents tagged with a profile other than the current working space are converted to and tagged with the working space profile.

•   Existing untagged documents use the current working space for editing but remain untagged.

•   For color data imported within the same color mode between either a non-color-managed source or destination, color numbers are preserved.

•   For all other import cases, colors are converted to the document’s color space.

Customizing advanced color management settings

When you select Advanced Mode at the top of the Color Settings dialog box, you have the option of further customizing settings used for color management.

Specifying a color management engine

The color management engine specifies the system and color-matching method used to convert colors between color spaces. For information about the specified engine, see the Description area of the Color Settings dialog box. (See “Setting up color management” on section 104.)

Specifying a rendering intent

Converting colors to a different color space usually involves an adjustment of the colors to accommodate the gamut of the destination color space. Different translation methods use different rules to determine how the source colors are adjusted; for example, colors that fall inside the destination gamut may remain unchanged, or they may be adjusted to preserve the original range of visual relationships as translated to a smaller destination gamut. These translation methods are known as rendering intents because each technique is optimized for a different intended use of color graphics.

Note: The result of choosing a rendering intent depends on the graphical content of documents and on the profiles used to specify color spaces. Some profiles produce identical results for different rendering intents. Differences between rendering intents are apparent only when you print a document or convert it to a different color space.


The following rendering intent options are available.

Perceptual    Known as the Image intent in Adobe PageMaker and Illustrator 8, Perceptual aims to preserve the visual relationship between colors in a way that is perceived as natural to the human eye, although the color values themselves may change. This intent is most suitable for photographic images.

Saturation   Known as the Graphics intent in Adobe PageMaker and Illustrator 8, Saturation aims to create vivid color at the expense of accurate color. It scales the source gamut to the destination gamut, but preserves relative saturation instead of hue, so when scaling to a smaller gamut, hues may shift. This rendering intent is suitable for business graphics, where the exact relationship between colors is not as important as having bright saturated colors.

Relative Colorimetric   This intent is identical to Absolute Colorimetric except for the following difference: Relative Colorimetric compares the white point of the source color space to that of the destination color space and shifts all colors accordingly. Although the perceptual rendering intent has traditionally been the most common choice for photo- graphic imagery, Relative Colorimetric —with the Use Black Point Compensation option selected in the Color Settings dialog box—can be a better choice for preserving color relationships without sacrificing color accuracy. Relative Colorimetric is the default rendering intent used by all predefined configurations in the Settings menu of the Color Settings dialog box.

Absolute Colorimetric   Leaves colors that fall inside the destination gamut unchanged. This intent aims to maintain color accuracy at the expense of preserving relationships between colors. When translating to a smaller gamut, two colors that are distinct in the source space may be mapped to the same color in the destination space. Absolute Colori- metric can be more accurate if the image’s color profile contains correct white point

(extreme highlight) information.

Using black-point compensation

The Use Black Point Compensation option controls whether to adjust for differences in black points when converting colors between color spaces. When this option is selected, the full dynamic range of the source space is mapped into the full dynamic range of the destination space. When deselected, the dynamic range of the source space is simulated in the destination space; although this mode can result in blocked or gray shadows, it can be useful when the black point of the source space is darker than that of the destination space.

The Use Black Point Compensation option is selected for all predefined configurations in the Settings menu of the Color Settings dialog box. It is highly recommended that you keep this option selected.

Using dither

The Use Dither (8-bit/channel images) option controls whether to dither colors when converting 8-bit-per-channel images between color spaces. When this option is selected, Photoshop mixes colors in the destination color space to simulate a missing color that existed in the source space. Although dithering helps to reduce the blocky or banded appearance of an image, it may also result in larger file sizes when images are compressed for Web use.


Desaturating monitor colors

The Desaturate Monitor Colors By option controls whether to desaturate colors by the specified amount when displayed on the monitor. When selected, this option can aid in visualizing the full range of color spaces with gamuts larger than that of the monitor. However, this causes a mismatch between the monitor display and the output. When the option is deselected, distinct colors in the image may display as a single color. Blending RGB colors

The Blend RGB Colors Using Gamma option controls how RGB colors blend together to produce composite data (for example, when you blend or paint layers using Normal mode). When the option is selected, RGB colors are blended in the color space corre- sponding to the specified gamma. A gamma of 1.00 is considered “colorimetrically correct” and should result in the fewest edge artifacts. When the option is deselected, RGB colors are blended directly in the document’s color space.

Saving and loading color management settings

When you create a custom color management configuration, you should name and save the configuration to ensure that it can be shared with other users and applications that use the Color Settings dialog box, such as Adobe Illustrator and Adobe InDesign. You can also load previously saved color management configurations into the Color Settings dialog box.

To save a custom color management configuration:

1   In the Color Settings dialog box, click Save.

2   Name your color settings file, and click Save.

To ensure that the saved configuration appears in the Settings menu of the Color Settings dialog box, save the file in one of the following recommended locations:

•     (Windows) Program Files/Common Files/Adobe/Color/Settings.

•     (Mac OS 9.x) System Folder/Application Support/Adobe/Color/Settings.

•     (Mac OS X) User/CurrentUser/Library/Application Support/Adobe/Color/Settings.

3   Enter any comments that you want to associate with the configuration, and click OK. The comments that you enter will appear in the Description area of the Color Settings dialog box when the pointer is positioned over the configuration in the Settings menu. To load a color management configuration:

1   In the Color Settings dialog box, click Load.

2   Locate and select the desired color settings file, and click Load.

When you load a custom color settings file, it appears as the active choice in the Settings menu of the Color Settings dialog box. If you load a settings file that has been saved outside the recommended location, it temporarily replaces the Other option in the Settings menu until another settings file is loaded.


Synchronizing color management between applications

The Color Settings dialog box represents the common color management controls shared by several Adobe applications, including Photoshop, Illustrator, and InDesign. If you modify and save over the current color settings file in any application other than Photoshop, you may be prompted to synchronize the common color settings upon starting Photoshop or upon reopening the Color Settings dialog box in Photoshop. Synchronizing the color settings helps to ensure that color is reproduced consistently between Adobe applications that use the Color Settings dialog box. To share custom color settings between applications, be sure to save and load the settings file in the desired applications. (See “Saving and loading color management settings” on section 112.)

Soft-proofing colors

 

 
In a traditional publishing workflow, you print a hard proof of your document to preview how the document’s colors will look when reproduced on a specific output device. In a color-managed workflow, you can use the precision of color profiles to soft-proof your document directly on the monitor—to display an on-screen preview of the document’s colors as reproduced on a specified device. In addition, you can use your printer to produce a hard-proof version of this soft proof. (See “Using color management when printing” on section 478.) The following diagram shows how the source document profile, proof profile, and monitor profile are used to represent colors in a soft proof.

 

A                                                       B                                                       C                                                        

Color-managed workflow:

A. Document space  B. Proof space  C. Monitor space

Keep in mind that the reliability of the soft proof is highly dependent upon the quality of your monitor, your monitor and printer profiles, and the ambient lighting conditions of your work station. (See “Creating an ICC monitor profile” on section 117.)

To display a soft proof:

1   Choose View > Proof Setup, and choose the proof profile space that you want to simulate:

•     Custom soft-proofs colors using the color profile of a specific output device. Follow the instructions after this procedure to set up the custom proof.

•     Working CMYK soft-proofs colors using the current CMYK working space as defined in the Color Settings dialog box.

•     Working Cyan Plate, Working Magenta Plate, Working Yellow Plate, Working Black Plate, or Working CMY Plates soft-proofs specific CMYK ink colors using the current CMYK working space.

•     Macintosh RGB or Windows RGB soft-proofs colors in an image using either a standard Mac OS or Windows monitor as the proof profile space to simulate. Neither option is available for Lab or CMYK documents.


•     Monitor RGB soft-proofs colors in an RGB document using your current monitor color space as the proof profile space. This option is unavailable for Lab and CMYK documents.

•     Simulate Paper White previews the specific shade of white exhibited by the print medium defined by a document’s profile. This option is not available for all profiles and is available only for soft-proofing, not printing.

•     Simulate Ink Black previews the actual dynamic range defined by a document’s profile. This option is not available for all profiles and is available only for soft-proofing, not printing.

2   Choose View > Proof Colors to turn the soft-proof display on and off. When soft proofing is on, a check mark appears next to the Proof Colors command.

When soft proofing is on, the name of the current proof profile appears next to the color mode in the document’s title bar.

To create a custom proof setup:

1   Choose View > Proof Setup > Custom.

If you want the custom proof setup to be the default proof setup for documents, close all document windows before choosing the View > Proof Setup > Custom command.

2   Select Preview to display a live preview of the proof settings in the document while the

Proof Setup dialog box is open.

3   To use a preset proof setup as a starting point, choose it from the Setup menu. If the desired setup does not appear in the menu, click Load to locate and load the setup.

4   For Profile, choose the color profile for the device for which you want to create the proof.

5   If the proof profile you chose uses the same color mode as the document, do one of the following:

•     Select Preserve Color Numbers to simulate how the document will appear without converting colors from the document space to the proof profile space. This simulates the color shifts that may occur when the document’s color values are interpreted using the proof profile instead of the document profile.

•     Deselect Preserve Color Numbers to simulate how the document will appear if colors are converted from the document space to their nearest equivalents in the proof profile space in an effort to preserve the colors’ visual appearances. Then specify a rendering intent for the conversion. (See “Specifying a rendering intent” on section 110.)

6   If needed, select any of the following:

•     Simulate Paper White to preview, in the monitor space, the specific shade of white exhibited by the print medium described by the proof profile. Selecting this option automatically selects the Simulate Ink Black option.

•     Simulate Ink Black to preview, in the monitor space, the actual dynamic range defined by the proof profile.

The availability of these options depends on the proof profile chosen. Not all profiles support both options.


7   To save your custom proof setup as a preset proof setup, click Save. To ensure that the new preset appears in the View > Proof Setup menu, save the preset in the Program Files/ Common Files/Adobe/Color/Proofing folder ( Windows), System Folder/Application Support/Adobe/Color/Proofing folder (Mac OS 9.x), or Library/Application Support/ Adobe/Color/Proofing folder (Mac OS X).

Changing the color profile of a document

In some cases you may want to convert a document’s colors to a different color profile, tag a document with a different color profile without making color conversions, or remove the profile from a document altogether. For example, you may want to prepare the document for a different output destination, or you may want to correct a policy behavior that you no longer want implemented on the document. The Assign Profile and Convert to Profile commands are recommended only for advanced users.

When using the Assign Profile command, you may see a shift in color appearance as color numbers are mapped directly to the new profile space. Convert Profile, however, shifts color numbers before mapping them to the new profile space, in an effort to preserve the original color appearances.

To reassign or discard the profile of a document:

1   Choose Image > Mode > Assign Profile.

2   Select one of the following:

•     Don’t Color Manage This Document to remove the profile from a tagged document. Select this option only if you are sure that you want the document to become untagged.

•     Working color mode: working space to tag the document with the current working space profile.

•     Profile to reassign a different profile to a tagged document. Choose the desired profile from the menu. Photoshop tags the document with the new profile without converting colors to the profile space. This may dramatically change the appearance of the colors as displayed on your monitor.

3   To preview the effects of the new profile assignment in the document, select Preview.



To convert colors in a document to another profile:

1   Choose Image > Mode > Convert to Profile.

2   Under Destination Space, choose the color profile to which you want to convert the document’s colors. The document will be converted to and tagged with this new profile.

3   Under Conversion Options, specify a color management engine, a rendering intent, and black point and dither options. (See “Customizing advanced color management settings” on section 110.)

4   To flatten all layers of the document onto a single layer upon conversion, select Flatten

Image.

5   To preview the effects of the conversion in the document, select Preview. This preview becomes more accurate if you select Flatten Image.


Embedding profiles in saved documents

By default, a tagged document will have its profile information embedded upon saving in a file format that supports embedded ICC profiles. Untagged documents are saved by default without embedded profiles.

You can specify whether or not to embed a profile as you save a document; you can also specify to convert colors to the proof profile space and embed the proof profile instead. However, changing the profile-embedding behavior is recommended only for advanced users who are familiar with color management.

To change the embedding behavior of a profile in a document:

1   Choose File > Save As.

2   Do one of the following:

•     To toggle the embedding of the document’s current color profile, select or deselect ICC Profile ( Windows) or Embed Color Profile (Mac OS). This option is available only for the native Photoshop format (.psd) and PDF, JPEG, TIFF, EPS, DCS, and PICT formats.

•     To toggle the embedding of the document’s current proof profile, select or deselect Use Proof Setup (available for PDF, EPS, DCS 1.0, and DCS 2.0 formats only). Selecting this option converts the document’s colors to the proof profile space and is useful for creating an output file for print. For information on setting up a proof profile, see “Soft- proofing colors” on section 113.

3   Name the document, choose other save options, and click Save.

Obtaining, installing, and updating color profiles

Precise, consistent color management requires accurate ICC-compliant profiles of all of your color devices. For example, without an accurate scanner profile, a perfectly scanned image may appear incorrect in another program, simply due to any difference in color space between the scanner and the program displaying the image. This misleading repre- sentation may cause you to make unnecessary, time-wasting, and potentially damaging

“corrections” to an already satisfactory image. With an accurate profile, a program importing the image can correct for any gamut differences and display a scan’s actual colors.

Once you obtain accurate profiles, they will work with all applications that are compatible with your color-management system. You can obtain profiles in the following ways, with the most precise methods listed first:

•     Generate profiles customized for your specific devices using professional profiling equipment.

•     Use the settings in the Custom CMYK dialog box to describe your device, and then save the settings as a color profile. (See “Creating custom CMYK profiles” on section 121.)

•     Obtain a profile created by the manufacturer. Unfortunately, such profiles do not account for individual variations that naturally occur among machines (even identical modes from the same manufacturer) or from age.

•     Substitute an available profile that may be appropriate for the device’s color space. For example, many Mac OS scanners have been optimized for an Apple RGB monitor color space, so you might try using an Apple monitor profile for these devices; for a


non-profiled Windows scanner, try substituting the sRGB color space. Be sure to proof images created with the profile before using the profile in production.

Adding device profiles to the color management system

You can add color profiles to your system so that they appear as choices in the Color Settings dialog box. To minimize confusion when working with profiles, delete any profiles for devices not used by you or your workgroup. Once you have added a profile to the recommended location on your system, you may need to load it or restart Photoshop so that the profile appears in the Color Settings dialog box.

Note: In Mac OS, you can organize the ColorSync Profiles folder by creating additional folders within it, or adding aliases to other folders. However, nested folders may cause conflicts with some applications, such as Adobe PressReady.

To add profiles to your system:

Copy profiles to one of the following recommended locations:

•     (Windows 2000) WinNT/System/Spool/Drivers/Color.

•     (Windows NT ) WinNT/System32/Color.

•     (Windows 98) Windows/System/Color.

•     (Mac OS 9.x) System Folder/ColorSync Profiles.

•     (Mac OS X) Users/CurrentUser/Library/ColorSync.

Note: If you use ColorSync 2.5 but have used earlier versions, some profiles may still be stored in the System Folder/Preferences/ColorSync™ Profiles folder on your hard disk.

For compatibility with ColorSync 2.5 or later, store profiles in the ColorSync Profiles folder in the System Folder.

Updating profiles

The color reproduction characteristics of a color device change as it ages, so recalibrate devices periodically and generate updated profiles. Profiles should be good for approxi- mately a month depending on the device. Some monitors automatically compensate for phosphor aging.

Also, recalibrate a device when you change any of the factors that affect calibration.

For example, recalibrate your monitor when you change the room lighting or the monitor brightness setting.

Creating an ICC monitor profile

Your monitor will display color more reliably if you use color management and accurate ICC profiles. Using an ICC monitor profile helps you eliminate any color cast in your monitor, make your monitor grays as neutral as possible, and standardize image display across different monitors.

On Windows, you can use the Adobe Gamma software (installed with Photoshop) to create a monitor profile. On Mac OS, you can use the Apple calibration utility to create a monitor profile. In addition, there are hardware-based utilities that you can use to create a monitor profile. Be sure to use only one calibration utility to display your profile; using multiple utilities can result in incorrect color.


Calibrating versus characterizing a monitor

You can use profiling software such as Adobe Gamma ( Windows) or the Apple calibration utility (Mac OS) to both characterize and calibrate your monitor. When you characterize your monitor, you create a profile that describes how the monitor is currently reproducing color. When you calibrate your monitor, you bring it into compliance with a predefined standard, for example, the graphics arts standard white point color temperature of 5000

Kelvin.

Determine in advance the standard to which you are calibrating so that you can enter the set of values for that standard. Coordinate calibration with your workgroup and prepress service provider to make sure you’re all calibrating to the same standard. However, if you have implemented a good color management workflow, you need not calibrate all monitors to the same standard; you simply need to characterize each monitor to produce accurate profiles.

About monitor calibration settings

Monitor calibration involves adjusting video settings, which may be unfamiliar to you.

A monitor profile uses these settings to precisely describe how your monitor reproduces color.

Brightness and contrast   The overall level and range, respectively, of display intensity. These parameters work just as they do on a television set.

Gamma  The brightness of the midtone values. The values produced by a monitor from black to white are nonlinear—if you graph the values, they form a curve, not a straight line. The gamma value defines the slope of that curve halfway between black and white. Gamma adjustment compensates for the nonlinear tonal reproduction of output devices such as monitor tubes.

Phosphors   The substance that monitors use to emit light. Different phosphors have different color characteristics.

White point   The coordinates (measured in the CIE XYZ color space) at which red, green, and blue phosphors at full intensity create white.

Guidelines for creating an ICC monitor profile

The following guidelines can help you create an accurate monitor profile.

You may find it helpful to have your monitor’s user guide handy while creating an ICC

monitor profile.

•     You don’t need to calibrate your monitor if you’ve already done so using an

ICC-compliant calibration tool and haven’t changed your video card or monitor settings.

•     Make sure that you are using a standard desktop (CRT ) monitor.

•     If you have the Monitor Setup utility (included with PageMaker 6.0) for Windows or the Knoll Gamma control panel (included with Adobe Photoshop 4.0 and earlier) for Mac OS, remove it; it is obsolete.

•     Make sure your monitor has been turned on for at least a half hour. This gives it suffi- cient time to warm up for a more accurate color reading.

•     Make sure your monitor is displaying thousands (16 bits) of colors or more.


•     Remove colorful background patterns on your monitor desktop. Busy or bright patterns surrounding a document interfere with accurate color perception. Set your desktop to display neutral grays only, using RGB values of 128. For more information, see the documentation for your operating system.

•     If your monitor has digital controls for choosing the white point of your monitor from a range of preset values, set those controls before starting the profiling utility. 6500 K is a good white point for most uses; 5000 K is the common standard for U.S. prepress providers.

•     Monitor performance changes and declines over time; recharacterize your monitor every month or so. If you find it difficult or impossible to calibrate your monitor to a standard, it may be too old and faded.

Calibrating with Adobe Gamma (Windows)

The ICC profile you get using Adobe Gamma uses the calibration settings to describe how your monitor reproduces color.

Note: Adobe Gamma can characterize, but not calibrate, monitors used with Windows NT. In addition, the ICC profile you create with Adobe Gamma can be used as the system-level profile in Windows NT. Adobe Gamma’s ability to calibrate settings depends on the video card and video driver software. In such cases, some calibration options documented here may not be available.

To use Adobe Gamma:

1   Start Adobe Gamma, located in the Control Panels folder or in the Program Files/ Common Files /Adobe/Calibration folder on your hard drive.

2   Do one of the following:

•     To use a version of the utility that will guide you through each step, select Step by Step, and click OK. This version is recommended if you’re inexperienced. If you choose this option, follow the instructions described in the utility. Start from the default profile for your monitor if available, and enter a unique description name for the profile. When you are finished with Adobe Gamma, save the profile using the same description name.

(If you do not have a default profile, contact your monitor manufacturer for appropriate phosphor specifications.)

•     To use a compact version of the utility with all the controls in one place, select Control Panel, and click OK. This version is recommended if you have experience creating color profiles.

At any time while working in the Adobe Gamma control panel, you can click the

Wizard button to switch to the wizard for instructions that guide you through the same settings as in the control panel, one option at a time.

Saving and loading working space profiles

If none of the working space options in the Color Settings dialog box accurately describe the color space of your particular output or display device, you can create a custom RGB, CMYK, Grayscale, or Spot working space profile. Saving your custom profile ensures that you can reuse it and share it with other users and other Adobe applications that use the Color Settings dialog box.


You can also load a profile that has not been saved in the recommended profile location, so that the profile appears in the Color Settings dialog box.

To save a custom profile:

1   Do one of the following:

•     In Windows and Mac OS 9.x, choose Edit > Color Settings, and select Advanced Mode.

•     In Mac OS X, choose Photoshop > Color Settings, and select Advanced Mode.

2   Create a custom working space profile. (See “Creating custom RGB profiles” on

page 120, “Creating custom CMYK profiles” on section 121, or “Creating custom grayscale and spot-color profiles” on section 125.)

3   Under Working Spaces, choose Save Color Space from the appropriate menu.

4   Name and save the profile. (See “Obtaining, installing, and updating color profiles” on section 116 for the recommended location to save the profile.)

To access a saved profile, you may need to load it or restart Photoshop. If you do not save a custom profile, it will be stored only in the custom color settings file of which it is a part and will not be available as a profile option in the Color Settings dialog box.

To load a custom profile:

1   Do one of the following:

•     In Windows and Mac OS 9.x, choose Edit > Color Settings, and select Advanced Mode.

•     In Mac OS X, choose Photoshop > Color Settings, and select Advanced Mode.

2   Under Working Spaces, choose Load Color Space from the appropriate menu.

3   Locate and select the desired profile, and click Open.

If you load a profile that has been saved outside the recommended location, it temporarily replaces the Other option in the Working Spaces menu, until another profile is loaded.

Creating custom RGB profiles

When designing a custom RGB profile, you can specify the gamma, white point, and phosphor settings of your monitor or RGB device.

To create a custom RGB profile:

1   Do one of the following:

•     In Windows and Mac OS 9.x, choose Edit > Color Settings, and select Advanced Mode.

•     In Mac OS X, choose Photoshop > Color Settings, and select Advanced Mode.

2   Under Working Spaces, choose Custom RGB from the RGB menu.

3   For Name, enter the name for the custom profile.

4   For Gamma, enter the gamma value you want to use.

5   For White Point, choose a setting.

For more information on gamma and white point settings, see “About monitor calibration settings” on section 118.


6   For Primaries, choose a set of red, green, and blue phosphor or primary types. This option is based on the different red, green, and blue phosphors or primaries used by monitors to display color. If the correct type is not listed, enter custom red, green, and blue chromaticity coordinates.

Note: Because you are defining the color space in which to edit images, the primaries do not have to match your monitor.

7   Click OK.

8   Save the custom profile. (See “Saving and loading working space profiles” on section 119.)

Creating custom CMYK profiles

When designing a custom CMYK profile, you can specify the ink colors, dot gain, separation type, and black generation of your output device. If you have saved Printing Inks and Separation Setup files from Photoshop 4.x or earlier, you can load them for use as a working space profile in the Color Settings dialog box. (See “Saving and loading working space profiles” on section 119.)

Custom CMYK profiles are mainly useful for providing color management compatibility with documents created in versions of Photoshop prior to 6.0. In general, the CMYK working space profiles included with the current version of Photoshop produce more accurate results.

Entering custom CMYK settings

Use the following instructions to create a custom CMYK profile.

To create a custom CMYK profile:

1   Do one of the following:

•     In Windows and Mac OS 9.x, choose Edit > Color Settings.

•     In Mac OS X, choose Photoshop > Color Settings.

2   Under Working Spaces, choose Custom CMYK from the CMYK menu.

3   For Name, enter a new name for the custom profile if desired. However, because the default name automatically reflects changes that you make to the Custom CMYK settings, it is recommended that you accept the default name.

4   For Ink Colors, choose an ink type. (See “Specifying ink colors” on section 122.)

5   For Dot Gain, specify a value. (See “Specifying dot gain” on section 123.)

6   Specify separation options. (See “Adjusting the separation type and black generation”

on section 124.)

7   Click OK.

8   Save the custom profile. (See “Saving and loading working space profiles” on section 119.)




Specifying ink colors

The Ink Colors menu lets you choose from the following options:

•     The preset ink options are designed to produce quality separations using standard inks and printing specifications. These ink standards differ slightly from one another. Similarly, the color and ink absorption qualities of the paper stock affect the final printed result. You can think of this information as telling Photoshop what printed cyan, magenta, yellow, and black look like given a certain set of inks and paper stock under your lighting conditions.

•     The Custom option lets you customize the on-screen display of ink colors to match printed output by entering values obtained from a color proof. (See “Printing a hard proof ” on section 127.) For example, you may want to use the Custom option to specify an ink set not listed as a preset option. When you change these settings, you change the profile that Photoshop uses to display the ink colors on-screen. See the following procedure for instructions on entering custom ink values.

•     If you have loaded a CMYK profile or color settings file that has been saved outside the recommended location, the ink setting for that profile or settings file temporarily replaces the Other option in the Ink Colors menu.

Note: In most cases, printing ink characteristics do not vary greatly from printer to printer within the same printer type. For example, one Tektronix Phaser II printer prints ink hues very similar to another one. But the amount of dot gain can vary significantly. Thus, for a different printer of the same type, you may have to change the dot gain setting in the CMYK Setup dialog box but not the printing ink colors.

To enter custom ink color values:

1   In the Custom CMYK dialog box, for Ink Colors, choose Custom.

By default, the Ink Colors dialog box defines colors using the CIE coordinates of Y

(lightness), x, and y values. The default ink sets are calibrated for viewing conditions of

5000 K (when viewed under D50 lighting), 2ฐ field of view. CIE coordinates are an interna- tional color definition standard supported by PostScript Level 2 and higher.

Note: Colors appear slightly different based on how much of the eye’s field of view they cover. The CIE has defined two standard ways of measuring color coordinates, one based on colors filling 10ฐ of the eye’s field of view, and one based on colors filling 2ฐ of the field of view. Photoshop uses the 2ฐ field of view standard.

2   If desired, select L*a*b Coordinates to enter the color box coordinates as Lab values rather than Yxy values. Use this option if your spectrophotometer only has Lab readouts.

3   Using your printed CMYK proof, take a reading of the color values using a spectropho- tometer, and then enter those values in the appropriate text boxes.

Alternatively, you can click the color box of the ink color you want to adjust and then adjust the color on-screen until it matches the patch on the color proof. Make sure that you are viewing the proof under the proper lighting conditions.

4   If desired, select Estimate Overprints to automatically estimate the overprint colors

(MY, CY, CM, and CMY ) using the CMYK and white values you entered. This is useful if you don’t have a spectrophotometer.


Specifying dot gain

Dot gain or loss can occur when the specified printer’s halftone dots change as the ink spreads and is absorbed by paper. As a general rule, you should not adjust the dot gain value until you have run a hard proof (which includes a calibration bar) and have measured the density values on the proof with a reflective densitometer. Adjust this value if your print shop has provided a different value for estimated dot gain.

The Custom CMYK dialog box gives you the following ways to specify a printer’s dot gain:

•     You can define a single dot gain value at the 50% level. This means that all four inks gain the same amount at 50%.

•     You can set up to 13 values along the grayscale range to create a customized dot gain curve for one or more CMYK plates. Use this method if your proof has a significant color cast in its neutral gray values.

To specify the dot gain at the standard 50% mark:

1   Print a hard proof with calibration bars included. (See “Setting output options” on section 473.)

2   Using a reflective densitometer, take a reading at the 50% mark of the printed calibration bar.

3   In the Custom CMYK dialog box, for Dot Gain, choose Standard. Then enter the total amount of dot gain measured by the densitometer. For example, if the densitometer reading is 54%, enter 4 in the text box to specify a dot gain of 4%.

Note: If you don’t have a densitometer, adjust the Dot Gain value until the image on- screen looks like the proof, and then add that value to your printer’s estimate of the expected dot gain between proof and final output.

To specify the dot gain using curves:

1   Print a hard proof with calibration bars included. (See “Setting output options” on section 473.)

2   Using a reflective densitometer, take a reading at one or more marks of the printed calibration bar.

3   In the Custom CMYK dialog box, for Dot Gain, choose Curves.

4   In the lower right of the Dot Gain Curves dialog box, select the ink plate for which you want to set dot gain curves. To set the same curves for all the plates, select All Same.

5   Do one of the following:

•     Enter the values of your densitometer readings in the text boxes.

For example, if you have specified a 30% dot, and the densitometer reading is 36%, you have a 6% dot gain in your midtones. To compensate for this gain, enter 36% in the 30% text box.

•     Click to add an adjustment point in the dot gain curve, and drag the point to change its value. The value then appears in the appropriate text box.


                                                                  

Adjusting the separation type and black generation

To make color separations, the three additive colors (red, green, and blue) are translated into their subtractive counterparts (cyan, magenta, and yellow). In theory, equal parts of cyan, magenta, and yellow combine to subtract all light reflected from the paper and create black. Due to impurities present in all printing inks, however, a mix of these colors instead yields a muddy brown. To compensate for this deficiency in the color separation process, printers remove some cyan, magenta, and yellow in areas where the three colors exist in equal amounts, and they add black ink.

A given color can be translated from RGB mode to CMYK mode in an endless number of ways. But prepress operators typically use one of the following ways to generate black in print:

•     In undercolor removal (UCR), black ink is used to replace cyan, magenta, and yellow ink in neutral areas only (that is, areas with equal amounts of cyan, magenta, and yellow). This results in less ink and greater depth in shadows. Because it uses less ink, UCR is used for newsprint and uncoated stock, which generally have greater dot gain than coated stock.

•     In gray component replacement (GCR), black ink is used to replace portions of cyan, magenta, and yellow ink in colored areas as well as in neutral areas. GCR separations tend to reproduce dark, saturated colors somewhat better than UCR separations do and maintain gray balance better on press.

Choose the type of separation based on your paper stock and the requirements of your print shop.

To adjust the separation type and black generation:

1   In the Custom CMYK dialog box, select a separation type.

The Separation Options area displays a graph based on current settings showing how neutral colors in the image will separate. In the graph, sometimes called a gray ramp, neutral colors have equal parts of cyan, magenta, and yellow. The horizontal axis repre- sents the neutral color value, from 0% (white) to 100% (black). The vertical axis represents the amount of each ink that will be generated for the given value. In most cases, the cyan curve extends beyond the magenta and yellow curves, because a small extra amount of cyan is required to produce a true neutral.

2   If you selected GCR as the separation type, choose an option for Black Generation:

•     None generates the color separation using no black plate.

•     The Light and Heavy settings decrease and increase the effect of the Medium setting

(the default). In most cases, Medium produces the best results.

•     Maximum maps the gray value directly to the black plate. This option is useful for images with a large amount of solid black against a light background, such as screen shots from a computer.


•     Custom lets you adjust the black generation curve manually. Before choosing Custom, first choose an option (Light, Medium, Heavy, or Maximum) that is closest to the type of black generation you want. This gives you a black generation curve to use as a starting point. Then choose Custom, position the pointer on the curve, and drag to adjust the black curve. The curves for cyan, magenta, and yellow are adjusted automatically relative to the new black curve and the total ink densities.

 

 
A

 

 

 
B

 

 

 
C

Black generation examples:

A. No black generation (Composite image, CMY, K)  B. Medium black generation (Composite image, CMY, K)  C. Maximum black generation (Composite image, CMY, K)

3   If needed, specify values for Black Ink Limit and Total Ink Limit (the maximum ink density your press can support). Check with your print shop to see if you should adjust these values.

In the Gray Ramp graph, these limits determine the cutoff points for the CMYK curves.

4   If you selected GCR as the separation type, specify an amount for undercolor addition

(UCA) to increase the amount of CMY added to shadow areas. Check with your print shop for the preferred value. If you are unsure of this value, leave it at 0%.

UCA compensates for the loss of ink density in neutral shadow areas. This additional ink produces rich, dark shadows in areas that might appear flat if printed with only black ink. UCA can also prevent posterization in subtle detail in the shadows.

Creating custom grayscale and spot-color profiles

You can create a custom grayscale or spot-color profile based on the specific dot-gain or gamma characteristics of your output device. You can also load a CMYK profile into the Gray working space menu to generate a custom grayscale profile based on the CMYK space. (See “Saving and loading working space profiles” on section 119.)


To create a grayscale or spot-color profile based on a custom dot gain:

1   Print a hard proof with calibration bars included. (See “Setting output options” on section 473.)

2   Using a reflective densitometer, take a reading at one or more marks of the printed calibration bar.

3   Do one of the following:

•     In Windows and Mac OS 9.x, choose Edit > Color Settings, and select Advanced Mode.

•     In Mac OS X, choose Photoshop > Color Settings, and select Advanced Mode.

4   Under Working Spaces, for Gray or Spot, choose Custom Dot Gain.

5   For Name, enter the name for the custom profile.

6   Do one of the following:

•     Using your densitometer readings, calculate the required adjustments, and enter the percentage values in the text boxes.

For example, if you have specified a 30% dot, and the densitometer reading is 36%, you have a 6% dot gain in your midtones. To compensate for this gain, enter 36% in the 30% text box.

•     Click to add an adjustment point in the dot gain curve, and drag the point to change its value. The value then appears in the appropriate text box.

•     Click OK.

7   Save the custom profile. (See “Saving and loading working space profiles” on section 119.)

To create a grayscale profile based on a custom gamma:

1   Do one of the following:

•     In Windows and Mac OS 9.x, choose Edit > Color Settings, and select Advanced Mode.

•     In Mac OS X, choose Photoshop > Color Settings, and select Advanced Mode.

2   Select Advanced.

3   Under Working Spaces, for Gray, choose Custom Gamma.

4   For Name, enter the name for the custom profile.

5   Specify the desired gamma value, and click OK.

6   Save the custom profile. (See “Saving and loading working space profiles” on section 119.)

Compensating for dot gain in film using transfer functions When using CMYK color profiles, you cannot customize dot gain settings. However, you may be able to compensate for dot gain from a miscalibrated imagesetter by using transfer functions.

Transfer functions enable you to compensate for dot gain between the image and film. For example, the Transfer function makes 50% dots in the image print as 50% dots on film. Similar to dot gain curves, the transfer functions let you specify up to 13 values along the grayscale to create a customized transfer function. Unlike dot gain curves, transfer functions apply only to printing—they don’t affect the image color data.


Use the following guidelines to determine the best method of accounting for dot gain:

•     If you are using a custom CMYK profile, use the dot gain settings in the custom CMYK

dialog box to adjust dot gain so that it matches the printed results.

•     If you are using an ICC profile and the dot gain values do not match the printed results, try to obtain a new profile with values that do match.

•     Use transfer functions only if neither of the previous methods is an option.

To adjust transfer function values:

1   Use a transmissive densitometer to record the density values at the appropriate steps in your image on film.

2   Choose File > Print with Preview.

3   Select Show More Options, and choose Output from the pop-up menu.

4   Click the Transfer button.

5   Calculate the required adjustment, and enter the values (as percentages) in the Transfer

Functions dialog box.

For example, if you specified a 50% dot, and your imagesetter prints it at 58%, an 8% dot gain occurs in the midtones. To compensate for this gain, enter 42% (50% – 8%) in the 50% text box of the Transfer Functions dialog box. The imagesetter then prints the 50% dot you want.

When entering transfer function values, keep in mind the density range of your image- setter. On a given imagesetter, a very small highlight dot may be too small to hold ink. Beyond a certain density level, the shadow dots may fill as solid black, removing all detail in shadow areas.

Note: To preser ve transfer functions in an exported EPS file, select Override Printer’s Default Functions in the Transfer Functions dialog box and then export the file with Include Transfer Functions selected in the EPS Format dialog box. (See “Saving files in Photoshop EPS format (Photoshop)” on section 448.)

To save the current transfer function settings as the default:

Hold down Alt ( Windows) or Option (Mac OS) to change the Save button to —> Defaults, and click the button.

To load the default transfer function settings:

Hold down Alt ( Windows) or Option (Mac OS) to change the Load button to <— Defaults, and click the button.

Printing a hard proof

A hard proof can help you check the accuracy of a custom CMYK working space profile. You can produce a hard proof by printing a CMYK image. Do not print an RGB image that has been converted to CMYK in Photoshop. Instead use an image that has been saved in CMYK format without an embedded ICC profile and whose CMYK values have been assigned directly in CMYK mode.


To create your own CMYK proof document:

1   Create a new Photoshop document in CMYK mode.

2   Use the Assign Profile command to remove any existing color profile from the document. (See “Changing the color profile of a document” on section 115.)

3   Create a set of swatches that includes the following:

•     Four swatches, each containing 100% of the CMYK colors (100% cyan, 100% magenta,

100% yellow, and 100% black).

•     Four combination swatches (100% each of magenta and yellow, 100% each of cyan and yellow, 100% each of cyan and magenta, and 100% each of cyan, magenta, and yellow).

•     A set of swatches that make up a four-color black, such as 60% cyan, 50% magenta,

50% yellow, and 100% black.

4   Print a hard proof with calibration bars included. (See “Setting output options” on section 473.)






Politica de confidentialitate



DISTRIBUIE DOCUMENTUL

Comentarii


Vizualizari: 542
Importanta: rank

Comenteaza documentul:

Te rugam sa te autentifici sau sa iti faci cont pentru a putea comenta

Creaza cont nou

Termeni si conditii de utilizare | Contact
© SCRIGROUP 2022 . All rights reserved

Distribuie URL

Adauga cod HTML in site