Task 8 How to Specify Photoshop Color Models

It is very important to specify how Photoshop is going to handle the color characteristics for each image file you open. These characteristics are divided between RGB color models (for screen viewing), CMYK color models (for offset printing), and grayscale conversions. Each model allows for a different range of color, which can dramatically impact the final design.

Choose Edit, Color Settings to open the Color Settings dialog box. You use this dialog box to set the default color spaces and color management options for all the files you open in Photoshop.

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Settings pop-up menu: graphics/1_icon.jpg Click the arrow to display a list of color management presets designed for specific tasks. Use the settings presets if you are unsure how to proceed, provided that your objective fits with the predefined settings. Options are Color Management Off, Colorsync Workflow (Mac only), Emulate Photoshop 4, Web Graphics Defaults, Photoshop 5 Default Spaces, as well as Europe, Japan, and US Prepress Defaults. Changing any of the menu listings that follow converts this setting to Custom.

Advanced Mode check box: graphics/2_icon.jpg Expands the window to show advanced controls.

Working Spaces Section

RGB pop-up menu: graphics/3_icon.jpg Click the arrow to display a list of RGB working space options:

Adobe RGB (1998): Presents a wide range of colors and works well for RGB-to-CMYK color conversions. As do all RGB models, the Adobe RGB option includes colors that fall outside the CMYK color range.

Apple RGB: Based on the original Apple RGB monitor (gamma 1.8, Trinitron primaries, 6500K white point). Works well for legacy graphics files because this was the standard for older versions of Adobe Photoshop and Illustrator.

ColorMatch RGB: Matches the color space of Radius Pressview monitors. This option should be used when working within that workflow environment.

SRGB IEC61966-2.1: Matches the native color range for most PC monitors and is becoming standard for many scanners, printers, and software applications. This option is ideal for Web work, but its small color range will cause problems for print production.

Monitor Profiles: If you have loaded a monitor profile for your current monitor, you may see a profile option for it in the RGB list. In this case, Photoshop acts as though all color management were turned off. This option should be used only if other applications in your workflow do not support color management.

Color Management Profiles: If other color management options are loaded on your system (such as ColorSync RGB), you may see profiles for them listed in the RGB list. The profiles you see listed usually reflect the current settings for each option.

CMYK pop-up menu: graphics/4_icon.jpg Click the arrow to display a list of CMYK color spacesfrom generic to industry-standard and custom settings. Choose from the Custom, Load, or Save CMYK, Euroscale, Japan, and US Prepress options. Check with your printer if you're unsure which setting to use.

Gray pop-up menu: graphics/5_icon.jpg This option specifies how grayscale images are displayed. Options reflect dot gain percentages (10%30%), 1.8 Gamma (Mac), and 2.2 Gamma (PC). Use dot gain percentages if you're going send the image to offset printing, as dictated by your printer.

Spot pop-up menu: graphics/6_icon.jpg This option specifies how spot color channels and duotones are displayed. Options reflect dot gain percentages (10%30%).

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Color Management Policies Section

RGB pop-up menu: graphics/7_icon.jpg Specifies mapping between different RGB color spaces, as may occur with embedded profile conflicts and the moving of profiles between multiple documents. Options include the following:

Off: Turns off color management when you are opening files or creating new files. In the case of mismatches between the working space and the embedded profile, the working space color model is used.

Preserve Embedded Profiles: Gives precedence to embedded profiles when you are opening files or creating new files. In the case of mismatches between the working space and the embedded profile, the embedded profile is used.

Convert to Working RGB: Gives precedence to the current RGB working space when you are opening files or creating new files. In the case of mismatches between the working space and the embedded profile, the working space color model is used.

CMYK pop-up menu: graphics/8_icon.jpg Specifies mapping between different CMYK color spaces, as may occur with embedded profile conflicts and the moving of profiles between multiple documents. Options include the following:

Off: Turns off color management when you are opening files or creating new files. In the case of mismatches between the working space and the embedded profile, the working space color model is used.

Preserve Embedded Profiles: Gives precedence to embedded profiles when you are opening files or creating new files. In the case of mismatches between the working space and the embedded profile, the embedded profile is used.

Convert to Working CMYK: Gives precedence to the current working space when you are opening files or creating new files. In the case of mismatches between the working space and the embedded profile, the working space color model is used.

Gray pop-up menu: graphics/9_icon.jpg Specifies mapping between different grayscale images, as may occur with embedded profile conflicts and the moving of profiles between multiple documents. Options include the following:

Off: Turns off color management when you are opening files or creating new files. In the case of mismatches between the working space and the embedded profile, the working space color model is used.

Preserve Embedded Profiles: Gives precedence to embedded profiles when you are opening files or creating new files. In the case of mismatches between the working space and the embedded profile, the embedded profile is used.

Convert to Working Gray: Gives precedence to the current working space when opening files or creating new files. In the case of mismatches between the working space and the embedded profile, the working space color model is used.

Profile Mismatches check boxes: graphics/10_icon.jpg Specify when you should be notified about profile conflicts. The Ask When Opening check box notifies you of mismatches as a file is opened and offers the option of overriding the embedded profile in favor of the current working space. The Ask When Pasting check box notifies you of mismatches when image data is brought into an existing file, as would occur through pasting, drag-and-drop, or importing.

Missing Profiles Ask When Opening check box: graphics/11_icon.jpg When you are opening a file, this option notifies you that there are no associated profiles and allows you to select one. Requires the related profile option to be turned on.

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Conversion Options Section

If the Advanced Mode check box at the top of the dialog box is enabled, the following options are available:

Engine pop-up menu: graphics/12_icon.jpg Specifies the color management system or method to be used when converting between color spaces. Options include the following:

Adobe (ACE): The Adobe Color Management System and Color Engine. Adobe recommends this option for most users.

Apple ColorSync (Mac only): Uses the Apple ColorSync color management and matching system, including associated hardware or software profiles.

Apple CMM (Mac only): Uses the Apple ColorSync color management system and the CMM color matching system.

Heidelberg CMM (Mac only): Uses the Apple ColorSync color management system and the Heidelberg CMM color matching system.

Kodak ColorSyncTM 2.0 compatible (Mac only): Uses the Apple ColorSync color management system and the Kodak ColorSync color matching system.

Color Management Profiles (Mac only): If other color management options are loaded on your system, such as ColorSync RGB, the Engine menu may list these profile options. The profiles you see listed usually reflect the current settings for each option.

Microsoft ICM (Windows only) Uses the Microsoft Windows color matching system.

Intent pop-up menu: graphics/13_icon.jpg Controls the method for mapping one color space into another. Options include the following:

Perceptual: Attempts to preserve the relative visual relationships between colors. This option works well with wide gamut images where exact color matching is not critical but a natural color space is desired.

Saturation: Requests high color saturation and bright colors. This option is good for business graphics or dynamic color effects.

Relative Colorimetric: Attempts to replicate the white point of the source file to the white point of the destination image. This option works well when the color range of both images is within the working color space.

Absolute Colorimetric: Does a direct match of source and destination images, without adjusting the white point. This option should be used when the exact match of a specific color is required (as with a logo). Colors outside the working color space will be flattened, and all contrast within these areas will be lost.

Use Black Point Compensation check box: graphics/14_icon.jpg Maps the black point as well as the white point when either of the colorimetric Intent options are selected. Selecting this check box ensures that the full color range of the working space is optimized.

Use Dither (8 bit/channel images) check box: graphics/15_icon.jpg Uses a color dithering method to specify colors when converting between color spaces. This option reduces banding but increases file size.

Advanced Controls Section

Desaturate Monitor Colors By check box and field: graphics/16_icon.jpg Allows you to desaturate colors by a prescribed percentage. This is a good option to use if you're trying to view an image with a color range that's larger than that of the current monitor.

Blend RGB Colors Using Gamma check box and field: graphics/17_icon.jpg Allows image colors to be created and combined using a specified gamma value. Gamma 1.0 is considered to be the most accurate with the sharpest detail. This option overrides any existing color spaces and is similar to the basic color controls used by other applications. The only reason I can think of for using this option is to match Photoshop to another application's color conversion process.

Description field: graphics/18_icon.jpg When you drag the mouse pointer over any of the sections and menus in the Color Settings dialog box, a short description of each appears in this field.

How-To Hints

Opening Files and Dialog Boxes

If you have checked the Ask When Opening check boxes in the Profile Mismatches section, you will get a dialog box each time a file is opened with a profile that does not match the current working space profile (as specified in the Working Spaces section). If Ask When Opening is selected in the Missing Profiles section, the dialog box appears each time a file is opened that has no profile at all. Although you can avoid these dialog boxes by disabling the Ask When Opening check boxes, you run the risk of unwanted color shifts as you open images. You're better off taking some time to understand which space works best for your workflow and image types, and managing the profiles through the controls described here.