What is the difference between saturation and brightness?

In Colors theory, what is the difference betw开发者_StackOverflow社区een saturation and brightness?

There's no point rattling off another 1-line answer because it's a rather large topic.

Wikipedia has this for HSL and HSV. Next there's an brief tutorial on Color Theory. Finally more on HSV And H2SV Color Space with some transformation code in C++.