Fundaments

So, before I was a game designer, I was a fine artist, even spent money to go to college for it! One of the hardest parts of moving to the digital scene was relearning color theory from scratch. Pigments work on subtractive color theory; that is to say, each pigment absorbs light of a specific frequency, and the result is the remainder of those frequencies that are reflected away. But the colors we see are the product of additive color theory, which is what happens when you combine different colored light sources together into a common output.

Visually speaking, additive color theory can be imagined as a sort of "sphere" of floating colors, with the color wheel itself making up the outer ring of the very center of the sphere. These represent full chroma colors; primaries, secondaries, and tertiaries. Full chroma in any given colors is a reduction of the total amount of light you could receive, and thus represents roughly the chromatic equivalent of "grey" when stripped of their hue. 

The color wheel has an inner ring called the tones, which is the product of each color being blended with 50% volume of its opposite color pigment. These are also known as the neutral colors, tones, or hues. They are closer to the actual greyscale the full chroma wheel represents.

When you increase the total spectrum output from all pigments, this turns the wheel into the next ring up. These are known as the pastel colors, and can generally be considered a sort of "light grey" corollary to the standard and tonal color wheel. In traditional paints, this is usually achieved by adding a highly reflective white pigment, to bleach out the resulting color the audience sees.

When you decrease the total spectrum output, you get the opposite result, everything shifts closer to black, creating a dark grey corollary to the color wheel, called the shades. This name comes from the fact that this is often achieved by adding some portion of a highly absorptive (often carbon based) black pigment to the base color, making a shadow of its previous brightness.

In either case, both the pastels and the shades cannot be considered fully chromatic, as both methods of brightening or darkening bring the color away from its original hue and closer to gray. This crates the charactaristic curved or diconal shape of subtractive color theory.

At the very core of the model is true neutral gray. At its highest pole is absolute all-spectrum reflection: white. Its opposite pole is full-spectrum absorption: black. These are often considered in classical color theory to not be "true" colors, as they lack any hue whatsoever, though younger minds have prevailed in proving that even electronics can't truly neutralize all hue from a beam of light outside of highly controlled laboratory conditions.