Algorithm to modify brightness for RGB image?

Question

I know there is formula for going RGB -> Luminance, but I need given a brightness parameter to modify the RGB values of an image. How do I do that?

Thanks

Answer 1

Map from RGB to HSL (Hue/saturation/luminance), keep the hue and saturation the same, and just modify the luminance and then do the backward mapping from HSL to RGB.

You can read more about the RGB to HSL and HSL to RGB transformations here.