Hello there,
After reading the CMYK vs. RGB thread, I thought it might be nice to give a few details. I started out doing web pages, and everything that I worked on was digital. However, I eventually needed to print work, and then even more eventually, I was hired as the lead designer for a mid-sized magazine, and those things meant that I needed to learn once and for all the definitve facts about CMYK and RGB.
RGB (Red, Green, Blue), is a color system that is designed for screens, and is in fact based on light. For that reason, it cannot be used to print, and if you print a document that is using the RGB color space, your printer will convert it for you. Think, for a moment, what would happen if you took three buckets of ink, one red, one green, and one blue, and dumped them on your kitchen floor. You would not, I promise, get a white puddle. It would be a disaster. However, if you combine those colors on your screen, (255 of RGB) you do get white. Why? Because RGB deals with light.
CMYK (Cyan, Magenta, Yellow, Black) is based off of ink. It is backed by a variety of color systems, the one most used here in the states of course being the Pantone system. If you get a Pantone book, you can flip through and find the right color, and then take the CMYK value from there. CMYK, unlike RGB, is indeed based in the real world. If your kitchen floor is currently white, and you want it to stay that way, you don’t put anything on it. Lets take those three buckets again, but this time, we’ll put Cyan in one, Magenta in another, and Yellow in the third. Dump those on your kitchen floor and you will not get black, you’ll get a horrid greyish mess. Take a fourth bucket full of black ink and mix it in, and you will indeed get black. You could have just dumped the black there in the first place though. (We might discuss ‘rich’ blacks later.)
You can see that in some ways, RGB and CMYK are almost opposite. RGB, the less you have of each color, the darker it is. The exact opposite is true with CMYK - the less you have the lighter it is.
When you create artwork that you intend to print, the choice is yours as to whether you use CMYK or RGB. For things like pictures, text, and solid elements (boxes, borders, etc) I always use CMYK. That said, if I was painting a digital picture, I would use the RGB color space because it is friendlier to work with, in my opinion, and the conversion process is ultimately fairly painless. Just make sure that you convert it before you send it to your printer, and when I say printer, I mean the guy who works for the firm with the presses, not the box sitting next to you.
To return briefly to ‘rich’ blacks, if you try to do a black and your solution is to simply put a value of 100% black (K) it may or may not print as a rich, pure, dark black. You should consider using a vlaule of 30/30/30/100 to get the kind of black that you’re looking for.
If you have any questions, please feel free to ask.
-Ryan
