Sh0oting Hoops: A Miniature Basketball Court
Somewhere In the Middle of a Very Large Football Field
The visible light spectrum can contain up to 16,777,216 colors. I say “can contain” because the human eye can detect at most several hundred thousand colors. This is the wide and wonderful world of RGB. By comparison, the 4-color printing space is only about 13,000 colors.
While at the Workbook, I used the analogy of basketball court/football field to describe the difference in the respective CMYK/RGB color spaces. Even those proportions are somewhat misleading, but I had to answer questions very concisely—I worked for a publishing firm, not a help desk.
The Color “F-Chart”
Eternal thanks to my boss Paul Semnacher, who kindly gave this to me.
Behold the Color “F-Chart”, which will help you trouble-shoot color issues in the CMYK color space.
The “F” in “F-Chart” euphemistically refers to “tamper, alter, distort” and so on. Use your imagination.
The primary colors are Yellow, Magenta and Cyan. The secondary colors (Green, Orange and Purple) are created from the primaries, as shown by the circular arrows. Black is not shown on this chart, as it controls contrast and shadow.
The main arrows in the center show where contamination occurs.
- Yellow dirties Purple
- Magenta contaminates Green
- Cyan contaminates Orange
Understanding these three things will solve most color issues in the proof stage.
While we’re here, there are several situations you will rarely see done well in 4-color printing:
- A clean orange
- Pure turquoise
- Iridescent lime green
- A neutral 4-color grayscale image.
You’re better off controlling it as a rich-black, (ie 20C and 100K).
Otherwise it will most likely be greenish. But people still try it, with predictably uneven results.
Out Of Gamut, Out Of Mind?
Sadly, no. Michael Kieran defines gamut as “The total range of colors produced by a device, system or storage medium. A color is described being out of gamut when its position in one device’s color space cannot be mapped into the the color space of another device”. Now we both know.
Common RGB Profiles
Here are some common RGB profiles. I’ve seen documents using all of these profiles—Quark, Photoshop, Indesign and Illustrator. Changing the profiles in your monitor, source application (Photoshop for instance) and in your layout program will have a noticeable difference in how color is treated.
- Apple 1998 is the smallest. However its range is considerably less than Adobe RGB (1998)
- Adobe RGB (1998) is in the middle. Consider it the convertible currency of color management—it produces good results with most RGB recorders and plays well in the CMYK translation.
- sRGB was designed for low-end consumer color scanners, digital cameras and inkjet printers. It is inadvisable for high-quality color production because of clipping in the blue-green part of the spectrum. Don’t use it if you are planning on printing it. Or you’re feeling foolishly lucky.
- Monitor RGB tailors color to the monitor, instead of the other way around. It makes sense in a web application, as it forces the RGB colors in Photoshop to match those in web-design programs like Dreamweaver. Again, this observation is from Michael Keiran. Since the bulk of my experience has been in print production, I cannot verify this absolutely. But I included it as an example of the spectrum of choices in color management.
In conclusion, color is a highly subjective experience. Customers sent target proofs ranging from the workmanlike to the surreal. I saw proofs on everything from cold bright white proofing stock (excellent), through warm off-white Arches paper (love that 5% yellow gain), on down to 24lb Walmart inkjet bond (they were out of paper towels that day). Never mind the sizes. I guess the ReadMe/FAQ was optional. But they all want Perfect Color.