Converting to CMYK
Step 22: Now you have your final color corrected version of the RGB image for this particular job. If your final output device is an RGB device, such as a film recorder or a video screen, your work is done. If you use a color management system or printer software that automatically converts your file from RGB to CMYK as you output it, you also are done. If your final output device is CMYK and you are going to do the conversion from RGB to CMYK in Photoshop, you need to make sure all the preferences are set up correctly for CMYK conversion and for this particular printing project. Choose Image/Mode/CMYK to convert the image to CMYK. When in CMYK, Photoshop automatically adjusts the image display on the monitor to try to simulate your actual CMYK printed output. Consequently, some of the brighter colors may get duller or change slightly. You might want to do additional small color tweaks now that you are in CMYK, using the same tools you used in RGB. You can also use the Selective Color tool and other tools to tweak CMYK colors, as explained at the end of Chapters 21: "Yellow Flowers," and 22: "Color Matching Images." When you are happy with your CMYK image, save it as KansasFinalCMYK.
Figure 20.42 Step 21: The final RGB version of Kansas after all color corrections and using the Unsharp Mask filter.