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| Color Management in Photoshop 5.x |
| Profile Setup |
The settings in Photoshop 5.x's Profile Setup dialog box determine how it handles older Photoshop files (called "legacy" files) and files from other non ICC-aware applications that have no profiles assigned to them. The settings also determine how Photoshop handles files that have profiles attached that don't match the default working color space:
Embed profiles
The Embed Profiles section of the dialog box is used to determine which files will have profiles embedded in them when saved. By default, profiles are embedded in all color-managed modes, RGB, Grayscale, CMYK, and Lab, when saved in any of the following graphic file formats: PSD, JPEG, TIFF, EPS, PDF, and PICT. Embedding profiles will only add slightly to the file's size. For most color-managed work you will want to embed profiles. There are, however, two instances when you won't:
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When creating a CMYK test file for calibration purposes where color values must be maintained in order to be reproduced and measured. |
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When working on images with strict palettes, such as computer UI design, and Web Palette Indexed Color files. |
The next two sections outline how Photoshop 5.x handles source profiles when opening files in Photoshop 5.x.
Assumed Profiles
To color-manage legacy files, Photoshop 5.x must assign a source profile to the files when they're opened. Photoshop assigns the profile based on the settings in the Assumed Profiles dialog box.
Two options are available from the pop-up menus in the Assumed Profiles dialog box for all three color spaces, RGB, CMYK, and Grayscale; these are:
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Ask When Opening: Photoshop prompts you to assign a profile to a file as you open it. |
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None: Photoshop will not assign a source profile, and will import the image data without conversion. This is the default setting for all files. |
For both RGB and CMYK, you can also select any of the RGB or CMYK profiles available on your system.
Profile Mismatch Handling
Photoshop 5.x uses Profile Mismatch Handling to address an embedded or assumed profile
that does not match the current color space in RGB, CMYK, or Grayscale Setup.
The options available from the color space pop-up menus are similar:
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Convert: Photoshop converts the image from the embedded or assumed color space to the color space you set in RGB, CMYK, or Grayscale Setup. In other words, Photoshop converts the color values in the file so they look correct within the current color space.
In the case of RGB or Grayscale files, the only conversion allowed is to RGB or Grayscale, respectively. CMYK files, however, can be converted to RGB or LAB color space, as well as CMYK.
However, converting an image from one CMYK space to another is not recommended because the image may suffer from "gamut compression," reducing the visible range of colors permanently. To maintain the color gamut of CMYK files, choose Ignore, or the RGB or LAB color space. |
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Ask When Opening: Photoshop prompts you to choose whether or not you want to convert. |
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Ignore: Photoshop ignores the mismatch and discards the existing profile. This may result in visible color shifts. This option is recommended for CMYK files. CMYK values will be maintained, and gamut compression will not occur. To compensate for the characteristics of your press, make tonal adjustments while monitoring the screen preview or the CMYK values reported by the Info palette. |
The default is set to Ask When Opening for all file types.
If you save a color-shifted file with an embedded profile, the color shifts will be "locked in" that file. This is because saving an embedded profile essentially means you want other applications to view the file just as it appeared in Photoshop.
In the case of calibration images, such as Olè No Moirè, you would want to choose Ignore to keep the existing color values. This will prevent the file from being converted to a different CMYK color space, which could change its color values and alter the results of the test.
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