Every once in a long while, I write something that I think fits this blog as well as my blog for writers.

Today, ladies and gentlemen, I’m doing it again. If you happen to read both blogs, please excuse the repetition….

A Primer on Web and Print Colors

I was in a class the other day and the teacher tried to get across the idea that mixing colors onscreen is different from mixing colors using actual paint. The paints mixed together makes a brown mess, while mixing colors onscreen makes white.

Is anyone else confused about this?

The Short Explanation

Paint absorbs light, while computer monitors create it.


Paint absorbs some light and reflects other light. The light it reflects hits our eyes.

SO: When light hits blue paint, most of the colors are absorbed and mainly blue light is reflected to your eyes. You see blue.

Red paint reflects mainly red light and absorbs the rest. Green paint reflects mainly green light. I think you get the point.

Let’s mix all those colors

Mix them up. The red paint still absorbs most of the blue and green light. The blue paint absorbs most of the red and green light. The green paint absorbs most of the red and blue light.

Hmm. That doesn’t leave much, does it? When we mix all the colors in paint, we get a mushy, ugly, brown, because no clear colors are being reflected to our eyes.

Paint: mixing all colors = very little color hitting our eyes (we see brown-black)


Here, we’re creating light, not reflecting light that was emitted elsewhere. When the screen shows red, it’s emitting red light. There’s nothing being absorbed.

What does this mean?

Let’s mix all those colors

We tell our paint program to show us full red, green, and blue. Now we’re adding to, not subtracting from, the light that reaches your eyes. It’s red plus green plus blue. The mix of all those colors comes to eyes as white.

Screen: mixing all colors = lots of color hitting our eyes (white)

And that about covers it. Or, I hope it does. And now, just for fun…

A Word about Color

Color (and light itself) is the way our eyes and brains interpret different electromagnetic wavelengths. (I promise that’s the last time I’ll say “electromagnetic” in this post.)

When the wavelengths are within a range that our eyes and brains can interpret, we call it visible light. (Radio waves, gamma rays, x-rays, and microwaves are all the same stuff, but at different wavelengths.)

When light has a shorter wavelength, it looks a little more blue. Longer wavelengths look a litter more red. Ultraviolet burns our skin, but the waves are too short for humans to see. Infrared shows up on those awesome military goggles, but otherwise the waves are too long.

Different things reflect and absorb different wavelengths. Black absorbs most of it, while white reflects most of it.

It’s interesting to me that a paint that we CALL green (let’s say) is actually reflecting green. That is, there’s nothing really green about the paint itself. It hates green light and loves other colors. But we call it green, poor thing.

Does this make sense? Does everyone already know this stuff? And also, did I get it right? I’m a writer, you know, not a designer or artist, so let me know!

One Response to Colors

  1. BruceS September 14, 2010 at 10:11 am #

    I think it’s cool that our eyes only pick up three colors, and the rest are sort of interpreted—why RGB monitors can make us think we’re getting yellow, etc. I’ve been wondering about the new TVs, that add yellow. But not wondering enough to overcome my laziness enough to research it. Where I work, we produce RBG graphics for on-screen (airplane cockpit equipment) use, and convert it to CMYK for printing to paper charts that nobody ever uses but the FAA requires. I had a friend who used to do that sort of thing as well, with some very sophisticated equipment (“Hunter colorometer”?) to make sure the CMYK matched the RBG as perfectly as possible. I doubt most people ever think about the fundamental difference between additive and subtractive colors. Color is a many-splendored thing.

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