Some of the hair color -- and skin color -- in TOS comes from the fact that Desilu Studios had no idea what they were doing half the time with the makeup -- because nobody had had this kind of television show before, They had to invent how much green tint to put on Spock's skin. They had to figure out how to do all of it. Those 'velour' uniforms? They're terrycloth towels, because toweling lasts well through washing after washing. Read up sometime on how the boots on the officers were lined with cardboard to hold them together.