Well, that's why she has me. There is nothing arbitrary about color theory, though there is a measure of subjectivity that figures into it. But there are rules to color and good design is conscious of them, even if the designer chooses to ignore them. Kind of like good grammar. I just used a sentence fragment, but it's OK for me to do that because I know it's a sentence fragment. So with my authority thus established, let me delve into some basics about color in general and how those basics relate to interior paints in particular.
Individual colors are described as having hue, value, chroma, shade, tone and tint. Put simply, hue is artist-speak for the actual color it is. Value is a description of how light or dark a color is. Chroma is how bright a color is. Shade describes the addition of black, tone describes the addition of gray and tint describes the addition of white.
Color wheels and circles have been around for centuries, and displaying colors in a circle emphasizes that they bleed into one another endlessly. You know; where red stops, orange takes over. Orange gives way to yellow, yellow to green, green to blue, blue to purple and then purple back to red.
The color wheel is also where we get the classical schemes of how to combine colors in a balanced way. Those basic schemes are monochromatic, complimentary, split complimentary, triad and analogous. There are many more named schemes than these five, but they are a good place to start.
A monochomatic color scheme uses tints and shades of the same color. Using a color like taupe on the walls of the room, a lighter tint of the same color on the trim and a darker shade of the same color on the ceiling is a good example of a monchromatic color scheme.
A split compliment combines hues to the left or right of a color's compliment on the color wheel. The purple, yellow and green of Mardi Gras in New Orleans are a split compliment.
A triad uses three colors that are equally spaced on the color wheel. In this example, red-orange, yellow-green, and blue-violet make up the triad. When using a triad in a room or in a home; one of the colors will be dominant, another secondary and the third will be an accent color.
Finally, an analogous color scheme uses consecutive colors on the color wheel. In this example, yellow, yellow-orange and orange combine to form an analogous scheme.
So with some terms now defined, we can move on to how this applies to the real world. I can show you examples of a split compliment and use colors that are easy to see when I'm writing a blog, but who wants a bedroom that looks like a New Orleans King Cake? Colors on a fan deck are far more nuanced and varied than what's shown on the simple color wheels here, but the concepts remain the same. And you needn't rely exclusively on paint colors to achieve a balanced color scheme. Upholstery, carpets, flooring, etc. figure into these equations too.
So if I want to use a split compliment in a dining room, I would choose a light sage-y green for the walls, a creamy yellow for the trim and then upholster the chairs in a lilac print. In approaching a room like that I used another guideline of color schemes called the 60-30-10 rule. 60-30-10 is a simple way to achieve a balanced room. The dominant color should cover 60 per cent of the surfaces in a room. The secondary color should cover 30 per cent and the final accent color should round out a balanced scheme.
If you're selecting this stuff on your own, spring for a color wheel and practice these combinations. If you stick to these basics you cannot make a mistake. Well, it's harder to make a mistake anyway.