Girls, girls, you're both pretty.
Whether black is a color depends on the context.
Maybe a physicist will tell you it's not. And maybe the physicist is right, in that context. So there, black is not a color. But if you have a black car, and I ask you what color your car is, you will (unless you're an insufferable pedant) say, "It's black." You will not say, "It's not any color; it's black." So there, black is a color. But if I have some photographs that are black and white, I can't call them color photographs. In heraldry, black (sable) is a color. But there's no black in a rainbow. But there is black in a box of crayons.
The metaphor was a prism, and when light is split by a prism, there's no black. So +1 for Cicero. But the whole argument is dumb, so -10 for everyone.