Most people have no idea what color temperature is. Only geeky artists ever use that term, and maybe a wayward interior decorator. But we all notice when an artist uses it well.
Color temperature is a measurable component of light, used by bulb manufacturers in lumens. For artists, it's the amount of warm or cool color in a painting and is based on the color wheel. Half the color wheel is warm, the other half is cool.
Notice in the example above that each color ALSO has a warmer/cooler version of itself on either side. For example; violet has a cooler version, blue-violet to the right, and a warmer version, red-violet to the left. Red has a warmer version; red-orange to the left and a cooler version; red-violet to the right. It goes around the wheel like this with every color.
Why this is important is to create color harmony and evoke a mood. Here's a subject I used from my Color Theory Class this week. I often print images in black and white so that I am only looking at the values. Color confuses the values, because you can make a transition using color temperature just as easily as you can make a transition using gradated values.
Here's the same subject but using cool colors (almost exclusively). Notice the "feel" of the painting. You get a sense of evening, calmness, quiet, peace.
Same subject, warmer palette, notice the change in time of day, emotional reaction, and energy level of the painting.
Suddenly it's an action painting filled with light and activity. The only real difference is the color temperature.
Normally, I would use a balance of the two, similar to a 50/50, 60/40 or even 70/30 if I want to make a statement. This creates a mood. Color balance is similar to dark/light balance. You want it to be uneven to create drama and interest.
Here's an example of a 50/50 color temperature painting:
I was pretty conscious of making the sky cooler, sail warmer, boat cooler against the warm sand, etc. Keep in mind that this is a white boat so all the color transitions are based on temperature. Good exercise for color temperature. No white is used in this.
Here's a more uneven approach of 60/40 color temperature with the emphasis on the cool side:
Main warms are in the yellow/greens, sea grapes with reds, and sand. Most of the cools are the blues, greens, violets in the shadows, sky and water.
Here's a more dramatic 70/30 split toward the warm side. Note the only cools are the cast shadows on the building and boardwalk. What mood do you get from this? Definitely a warm sunny day feel!
This was a plein air study of Scully's restaurant on John's Pass and was painted in noon sun. See how color temperature plays a major role in this painting?
As an artist, you get to manipulate your viewer through skillful color use and composition. If you want to learn more about color temperature, set up a white still life in the sun and paint it without using pure white. Nothing will make you grow quicker than challenging your artist's eyes to see the subtle differences in color temperature and the color of light.