Why do most people who draw rainbows leave out the sixth or indigo ray?

Answer 1

Contrary to popular belief, indigo is not one of the main colors of the rainbow, therefore unnecessary to use when drawing one because it will automaticaly appear where the blue and violet bands blend together. There are only six basic colors; they just stuck indigo on because they thought there "ought" to be seven, the "perfect number." In fact, orange isn't one of the main colors either. Colors like it and indigo are called tertiary colors, made by combining a primary color with a secondary color. This misconception is because most think the primary colors are red, yellow, and blue. While this seems to work with pigments(actually it doesn't quite work), like paint, crayons, etc., keep in mind that a rainbow is made of light, not paint. Light color mixing is different. With light, the primary colors are red, green, and blue. The secondary colors are yellow, cyan, and fuchsia(or violet). Interestingly enough, these are also the real primary colors for pigments! Yellow, cyan, and magenta can be used to create red, green, and blue. That's why color printers use those colors in their cartrages. Well, that should more than answer your question, and it's good to know about the spectum. If you think you could learn even more about colors and not get bored into unconsiousness, and you want to do so, look for a question I'll post later. It's in the art section; search for "12 main colors."