Color Management: Photoshop Color Settings
Now that we've covered some of the background of what color management is all about, it's time to start putting some of this to practical use, and the first place to go is your Photoshop Color Settings. At the bottom of the Edit menu but not part of the regular Preferences is the Color Settings option. This is where you select your working space and some of the default settings that affect how profiles are converted.
I mentioned week before last that Adobe RGB 1998 makes an excellent choice for your Photoshop working space. Lest you think I wasn't going to get around to telling you how to set this, this is the place. The working space in Photoshop determines the color space in which your documents live by default. In order not to limit yourself, you want a color space with a wide enough gamut to encompass as many colors as possible. At the same time though, you only have 256 possible values for each of red, green and blue to work with. Any combinations that represent colors you will never make use of would be wasted.
Modern inkjet printers such as the Epson 2200 that I currently print on have a gamut wider than most other output options you are likely to make use of — certainly wider than your monitor or any commercial CMYK printers. We don't want to use it as our working space though since some day we might have a different printer, and, as good the Epson 2200 is today, not everyone has one and we might just want to share files with other people. So, we need a standard, abstract color space that everyone can deal with that comes reasonably close to matching the gamut of printers like the 2200 as practical.
Adobe RGB 1998 fits all these requirements rather well. The image shown at left graphically represents the universe of all possible colors (obviously everything has been toned down to some degree or we'd never be to display it on a monitor). The irregularly shaped outline within the colored area represent the gamut of the Epson 2200. The smaller triangular outline shows the sRGB gamut used as a standard for computer monitors and the larger triangle maps the gamut of Adobe RGB 1998. Now you can probably see why Adobe RGB is so popular as a working space.
Now, it's time to open the Color Settings in Photoshop. Make sure you have the Advanced Mode option checked so you can see everything the dialog box has to offer. You should see something like what is shown here. Photoshop can do a lot of things and many of these settings have no bearing on we are going to be talking about here so I'm going to ignore them, but there are a number that are important. Right at the top of the list of these is the RGB Working Space. This is where Adobe RGB 1998 goes.
Next, under Color Management Policies, there are a number of options that determine the default behavior of Photoshop when you convert from one profile to another and whether you want it to take these actions without asking you or not when you do various things. You'll find that in most cases when you convert profiles though you have the option of overriding these defaults so they mainly just affect the specific situations that have check boxes listed here. At least for now, I'd recommend setting these to what I have shown here. You can always change them later if, after using Photoshop for a while, you get tired of constantly being asked when you open a file (such as a jpeg saved for the web) that doesn't have a profile or do any of these other actions. By then you will be more familiar with what they do to make choices that best fit your workflow.
The Engine drop down list in the Conversion Options determines which Color Management Module you want to use by default. On Windows these days you get choices of "Adobe (ACE)" and "Microsoft ICM." Mac OS obviously substitutes ColorSync for Microsoft. For the trivia buffs, ACE stands for the Adobe Color Engine and is built into Photoshop and many other Adobe products. While all these CMM's should be fully ICC compliant, there may be subtle differences. I recommend you use Adobe (ACE) since it's the only option that is cross-platform, existing on both Windows and Mac.
Under this is the default Rendering Intent you want to use. For every conversion that really matters you can override this. Since your working space will have a gamut larger than most files without profiles you may be dealing with, you are reasonably safe setting this to any of the options,
We only need to deal with a few more settings. Black Point Compensation insures that black in one color space is mapped to pure black in the target color space. Dithering conversion of 8-bit per channel images keeps tonal gradations as smooth as possible. At the bottom under Advanced Controls, make sure you have both Desaturate Monitor Colors and Blend RGB Colors Using Gamma.... unchecked. While this is the default for both, some people may have inadvertently changed them in the past.
There you have it. You can save these settings with a name to call them up later by clicking on "Save...." If you've really messed things up, you can click on Cancel instead or simply hold down the Alt key (Option key on Mac) and the Reset button will turn into a Reset button. Both Photoshop CS and 7.0 work the same in this regard so don't worry if you haven't upgraded yet. There are plenty of other reasons to upgrade to CS, but color management works essentially the same in both.
The next area to be tackled is profiling your monitor, but I'll save that for next week.