Color Management Settings - CMYK Basics, Part II

The CMYK color mode is used primarily with images destined for four-color printing on huge commercial printing presses. Even if you never prepare an image for press, you might need to load a CMYK color profile. Many inkjet printers now come with CMYK profiles, even though their print drivers still require that you send RGB data when you print.

Edit> Color Settings opens the dialog box that allows you to load an appropriate profile. From the CMYK pop-up menu, select Load CMYK.

The Load dialog box, for both Windows and Mac, will show you available color profiles, whether they are appropriate or not. Photoshop installs a variety of profiles in the Application Support folder. (If you attempt to load a file that is not a CMYK profile, Photoshop will show you an error message.)

Here are the general guidelines:

If you will be sending the job to a print shop, call the printer and ask what settings are appropriate. Different papers, different inks, different printing presses all have an impact on color management.

If you'll be outputting to an inkjet printer (other than a high-end proofer), select the appropriate profile, if available (see the first image above for examples of Epson profiles). If your inkjet doesn't have profiles, choose Generic-CMYK.

If you will not be printing your images at all, if for example you do only Web graphics, the CMYK profile is insignificant. Choose Generic-CMYK.

In the event that you call your printer and get a shrug and an "I dunno," you can select the best available CMYK profile with answers to two questions: Will the job be printed on coated stock or uncoated stock? Will the job be run on a sheetfed press or a web press? (For the record, that use of "web" has nothing to do with the Internet.) In the image below, you can see the four major options.

(Photoshop also installs, by default, appropriate settings for use in Europe and in Japan.)

So, what do you do if the printer actually gives you some info? The shop may send you a profile on disk or as an e-mail attachment, or may have you download a profile from their Web site. If that's the case, simply use the Load CMYK command. If, on the other hand, you get numbers for Black Ink Limit, Total Ink Limit, and so forth, choose Custom from the CMYK pop-up menu in the Color Settings dialog box. That will open this box:

Your printer may have instructed you to load a preset profile, which you can select from the Ink Colors pop-up menu:

You may even need to generate a custom black ink curve. If so, select Custom from the Black Ink Limit pop-up menu.

You'll be able to create a custom black ink curve by clicking on the line and dragging points. (The mechanics of the curve are similar to those of used in Photoshop's Image> Adjust> Curves dialog box.) To the lower left is the amount of black ink in lighter areas of the image, to the upper right is the amount of black ink for shadow areas.

Whether you create a custom black ink curve or not, clicking OK will automatically load the CMYK profile in the Color Settings dialog box.

Keep in mind that you should create custom CMYK profiles only at the advice of your printer. Embedding a false profile can lead to very unexpected - and unwanted - color reproduction.