Then, convert the images to CMYK prior to placing the TIFF files in your page composition document (an InDesign file, for instance). Long books have been written to explain all the nuances of color theory and color conversion, but the most reliable rule of thumb is to make all corrections to your images within the RGB color space. It is also easier to achieve color balance in RGB color space than in CMYK format, since a neutral color contains equal amounts of the three hues (which is not exactly true in the 4-color-CMYK-color space). The files are also smaller, interestingly enough, since you are defining color in three channels rather than four. Therefore, you have more color image 'information' to work with if you keep the photo in RGB format for as long as possible. Another way of saying this is that your color monitor can reproduce many more colors than can be printed on press. RGB is a much larger color space than CMYK. The big question is, when do you make the conversion and why? You will then convert these images to the CMYK color space prior to handing off final art files to your offset print provider.

If you are preparing art files for final offset or digital printing, you will normally scan images, or open scanned images in Photoshop, into the RGB color space. Additional black ink is then added to achieve a true black.

In contrast, color on a printing press is created with ink (cyan-magenta-yellow-black, CMYK, or subtractive color), and the presence of equal amounts of CMY yields K (black, or, more precisely, a dirty brown). The presence of equal amounts of all colors creates white light.

Following is an elaboration on this important topic.Ĭolor on the monitor is created with light (red-green-blue, RGB, or additive color). Several years ago I wrote a short PIE Quick Tips article describing the difference between RGB and CMYK color and noting that you must convert RGB images to CMYK images prior to submitting a job to your offset or digital print provider. When to Convert an Image from RGB to CMYK

How to adjust rgb offsets