Formula to determine brightness of RGB color

Question

I\'m looking for some kind of formula or algorithm to determine the brightness of a color given the RGB values. I know it can\'t be as simple as adding the RGB values toget

Answer 1

Interestingly, this formulation for RGB=>HSV just uses v=MAX3(r,g,b). In other words, you can use the maximum of (r,g,b) as the V in HSV.

I checked and on page 575 of Hearn & Baker this is how they compute "Value" as well.