It’s All About Color, part two

Now that we’ve talked a little about color theory and how we get the various colors from mixing primary color, let’s talk about additive and subtractive color. Subtractive color is what you see when you are looking at anything in print. From newspapers to books to those tempting invitations you receive for some event, every printed piece uses  subtractive color. So do artists, house painters, and virtually anyone coloring a tangible surface. In contrast, everything you see on the screen, be it computer monitor, television or a projected slide show presentation, uses the Additive color. We view these colors every day, but most of us have no idea how they are created.

First let’s talk about Additive color. In Additive color, color mixing is done with light. In the early 1800’s Sir Thomas Young proposed that he could make most colors in the visible spectrum by just mixing red, green and blue light, what we now refer to as RGB color. When red and blue are mixed, they create magenta, when red and green are mixed, they create yellow, and when blue and green are mixed, they create cyan. When all six colors combine, they create white, or a lack of color. This is how your television sees every visible color. The screen contains thousands of little light dots that emit red, blue and green light to create the colors for the images we see.

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Now let’s talk about subtractive color. In order for the human eye to see color on a tangible surface, the object’s surface must give off or reflect light when struck by white light. A color will either absorb or reflect the light (the amount depending on each hue), allowing the eye to see that specific color. Something that reflects 100% of light is seen as white, If 100% of the light is absorbed, it is seen as black.  So every color reflects/absorbs some percentage of light. Subtractive color uses the three primary colors of red, yellow, and blue to create all other colors in the world of painting, and in the world of print or process color, its three primary colors are cyan, magenta, yellow, (with an added black) or CMYK.

Not all color systems are equal; something to keep in mind when you are viewing color on the screen. RGB color has more visible hues than that of CMYK, so what you see on the screen, doesn’t always translate to a color in print. The image below shows the limits of RGB color verses CMYK. RGB includes more saturated colors (those on the outer edges of the circle), than can be made with CMYK. This is why color on TV or a computer screen is more vibrant. When a designer wants a color that can’t be duplicated with CMYK, they choose a a Spot color; a special pigmented color mix that has its own color pass through the press. This would be where the Pantone Matching System or Trumatch come into play.

rgb-cmyk-gamut

There are other terms used when talking about color such as gamut, chroma, value, and purity but to keep this a bit less confusing, I’ll just stick to the basics for now. For more in depth information on color, please visit RGB World