Better CMYK Conversions

I suggest that you leave your image in RGB mode when printing to an ink jet printer. Even though the printer uses cyan, magenta, yellow, and black ink, Photoshop uses the same software that draws your screen image to send information to the printer. That software only handles RGB information, so there is no advantage to printing from CMYK. Postscript language printers can bypass that screen-drawing software and therefore can produce acceptable results from either RGB or CMYK mode.

You'll want to convert your images to CMYK mode if they will be printed on a commercial printing press. The traditional way of doing that is to simply choose Image > Mode > CMYK. That's fine if you're in a hurry, but by doing that you are bypassing a bunch of settings that might make your image look better. Here's your alternative: Choose Convert to Profile from the Edit menu in CS2, or the Image > Mode menu in CS (Figure 7.41). It looks complicated, but it's not. The top just tells you the colors of RGB that your image is made from (that's known as your source space). Then, as long as you've set up the CMYK working space to what's right for your printing conditions, all you have to do is choose Working CMYK from the Destination Space pop-up menu. And now all that's left is to play with the Intent pop-up menu and those two check boxes to see which combination of settings will produce the best result. Earlier, I kind of glossed over what the Intent pop-up menu does, so let's take a look at the choices that are available. Most images will start off with many colors that are just too vivid to be reproduced in CMYK mode (known as colors that are out of gamut for you techie folks). When you convert to CMYK mode, Photoshop has to do something with those colors to get them into the range of what can be reproduced on a printing press. The choices in the Intent pop-up menu determine how Photoshop will deal with those out-of-gamut colors.