Let's start with color basics -- that is primaries, secondaries, and tertiary colors. There are 3 and only 3 primary colors: Red, Blue, and Yellow. These are colors that CANNOT be mixed from any other color. But the great thing about the primaries is that they can make all the other colors. When two primaries are mixed together they are called secondaries: Red and Yellow = Orange; Yellow and Blue = Green; Red and Blue = Purple. A tertiary color is one that is, for example, more on the red or yellow side of orange, or more on the blue or yellow side of green, or more on the blue or red side of purple. Remember those wonderful Crayola crayons? Some were called 'blue green'. That is one tertiary color. As you can see, all the colors are variations of these six – red, yellow, blue, orange, green and purple.
Complimentary or opposite colors are opposite each other on the color wheel and are used to dull a color down. For example, to dull down red, add some green. To dull down blue, add some orange, etc…. These colors are opposite of each other on the color wheel. An easy way to remember what the complementary color is to any of these basic 6 colors is to remember how the color is made in the first place and then add the third color that is missing from the triad. For example, to find the opposite of purple ask yourself how do you make purple? Red + Blue. What’s missing? Yellow! Hence, yellow is the opposite of purple. What is the opposite of Blue? What colors are missing in the triad? Red and Yellow. Red and Yellow make orange. Hence, Orange is the opposite of Blue. Eventually the color gets so dull it will be a neutral color and will be in the middle of the wheel. In other words, it will be grey.
OK.....now that we are all on the same page let's look at what Stern starts with as a simple set up and see and compare the results.
The background is still going to have a greenish cast, but the red foreground is bouncing light back on to the background. Notice that the background is now a cooler dull green than the previous set up. If you remember that red and green are opposites on the color wheel, you can understand why this is happening. Everything in the set-up is going to be affected by the light and colors surrounding it so the red is bouncing its color on to the black cloth. The top of the tissue is a bit grayer than the previous set-up, but still on the warm side. But the side of the tissue is now a purplish-grey. The reason is that white is cool and the red is mixing with that cool color and moving it toward the purple. In addition, the black cloth is bouncing its color on to the red, and because black acts like blue, it is mixing with the red to make the purple tone.
I hope you are finding this as interesting as I am. As I paint more of these exercises I will post the results and try to explain why things are happening as they are. I always welcome your thoughts and comments.