Color Management Settings

We've looked at establishing an RGB profile and at choosing your CMYK settings. Now let's see how the whole thing comes together in Photoshop's Color Settings dialog box.

You'll see the following set of options:

Before we do anything else, check the Advanced Mode box in the upper-left corner. This expands Color Settings to show additional options.

At the top of the box is a pop-up menu with a variety of presets.

Choose a starting place from this list if you'd like, or adjust all settings individually. If you do choose a preset, the menu will later show Custom when you switch to your monitor profile. Mac users who rely on ColorSync for color management from program to program can simply choose that setting from the list. It allows the system's color management to handle all display and conversion work for you. (Photoshop and ColorSync seem to have a very good working relationship under most circumstances.)

Emulating Acrobat 4 coordinates Photoshop with Acrobat for CMYK consistency. If you're using an Acrobat pre-press workflow, this is worthy of consideration. If you do primarily pre-press work, it's possible that the US, European, or Japanese presets will be suitable, but consider them to be "starting points" and load your own monitor profile and adjust other settings as necessary. The Web Graphics Defaults option uses the sRGB color space. While that's okay for most Web uses, it is highly recommended that you avoid sRGB for any print work. It should also be noted that most of the presets use Windows gamma (discussed below).

The next step, whether you've opted for settings from the presets or not (except ColorSync), is to load your custom monitor profile. (We looked at using Adobe Gamma to calibrate monitors in Part I of this series.) Choose Load RGB from the RGB pop-up menu in the Working Space section of the dialog box.

If you have a custom CMYK profile from your printer, you can use the Load CMYK option from the CMYK pop-up menu.

Custom CMYK profiles are developed for a specific printing press, printing under specific conditions. Always check with your print shop about using custom profiles. Such profiles, by the way, should have the file extension .icc attached to the file name.

Next in the Working Space section of the dialog box is Gray Gamma.
This affects how images will be shown on-screen.

Generally, Mac users should choose Gray Gamma 1.8, while Windows users should use Gray Gamma 2.2. There are a number of exceptions. If, for example, you work in a closed-loop printing operation, take the time to establish an appropriate dot gain setting. This allows you to simulate expected dot gain on screen. If you work primarily for the Web and use a Mac, you may want to consider using the Windows gamma in order to see what the majority of Web surfers will see. (You can also leave the gamma at 1.8 and use Photoshop's menu commands View> Proof Setup to select Windows RGB and View> Proof Colors to see the effect.)

The fourth pop-up menu for Working Spaces is Spot. This choice affects only spot color channels. It should be set for the particular printing situation. Check with your printer for the appropriate dot gain setting. When in doubt, Dot Gain 20% is the safest choice.

The next section of the Color Settings dialog box is Color Management Policies. You have three pop-up menus, one each for RGB, CMYK, and Grayscale images. They each offer three choices:

Off: This choice ignores any color profile embedded in the file and does not convert the image's colors to the working space.

Preserve Embedded Profiles: If the image has been saved with a color profile, Photoshop will retain it.

Convert to Working (color space): This option allows Photoshop to take advantage of your custom RGB and CMYK profiles.

Generally speaking, you want to convert RGB and CMYK images to your working profile. There are, however, exceptions. For example, if an image is sent from one computer to another, and will later be returned to the first computer for additional work or output, retaining the embedded profile makes sense.

Color management for grayscale images should be turned off to preserve the tonal range. Retaining or embedding profiles can clip the image.

The Color Management Policies area of the dialog box also offers checkboxes that allow you to choose whether or not Photoshop will tell you when a color conversion is required. Checking these boxes is optional.

The lower part of the Color Settings dialog box is only available when the Advanced Mode box is checked in the upper-left corner.

A pop-up menu offers several choices of "engines" to handle color conversions between RGB and CMYK. Adobe is generally a good choice for Photoshop work. If, however, you work with images in additional, non-Adobe, programs, you may want to use another CMM. Kodak Digital Science or Apple ColorSync may be more appropriate. (If you're using ColorSync elsewhere, that may be the right option for you.) Generally speaking, for most Photoshop users, Adobe is an appropriate choice.

The Intent pop-up lets you choose how to handle color conversion when some colors are outside the target gamut. Such colors need to be brought back into gamut in order to be displayed.

Perceptual: This choice maintains the relationships among colors as much as possible. You may see an overall change in color, even colors that are not out of gamut, in order to preserve the general appearance of the image.

Saturation: The saturation values of all colors are maintained. Out of gamut colors are shifted in hue and perhaps lightness to be brought into gamut. Graphics such as business charts and presentation slides can benefit from saturation retention. Generally speaking, this isn't a good choice for most photographic images. (The exception would be, of course, images that are highly saturated and need to stay that way for effect.)

Relative Colorimetric: Out of gamut colors are brought into gamut by adjust the hue and saturation. Lightness values are maintained. This is generally the best choice for Intent.

Absolute Colorimetric: This choice doesn't attempt to match the white point of the source color space to the white point of the target color space. For that reason it generally produces poor color conversions. This Intent may be appropriate for cartoon and logo artwork under some circumstances.

In this section of the Color Settings dialog box you'll also see check boxes for Black Point Compensation and Use Dither (8-bit/channel). Black Point Compensation maps the darkest neutral colors between the source and target color spaces. When unchecked, the darkest neutral color is always mapped to black, which can result in some color shifts. The other checkbox allows Photoshop to use dithering to help prevent banding during color conversion. It's generally a good idea to use this option.

Also available only when Advanced Mode is checked are the Advanced Controls checkboxes.

Desaturate Monitor Colors By: Desaturating the monitor colors can be useful when detail is lost in the brightest and lightest colors. Generally, leave it unchecked.

Blend RGB Colors Using Gamma: Leaving this unchecked allows Photoshop to use your selected working space without interference. Checking the box overrides the settings.

While color management remains mysterious to many of us, these basic guidelines can establish a suitable working environment for most Photoshop users, most of the time. Remember, "Your mileage may vary!"