How to check if hex color is “too black”?

Question

I\'m trying to evaluate the darkness of a color chosen by a color picker to see if it\'s \"too black\", and if so, set it to white. I thought I could use the first character

Answer 1

There's an important distinction here between luminance and brightness. Luminance, at the end of the day, is a measure of how much energy travels through a certain area and completely ignores how our perceptual systems perceive that energy. Brightness, on the other hand, is a measure of how we perceive that energy and takes into the account the relationship between luminance and our perceptual system. (As a point of confusion, there is a term called relative luminance, which seems to be used synonymously with brightness terms. It tripped me up good).

To be precise, you are looking for "brightness" or "value" or "relatively luminance" as others have suggested. You can calculate this in several different way (such is to be human!) http://en.wikipedia.org/wiki/HSL_and_HSV#Lightness

1. Take the max of R, G, and B.
2. Take the average of the max and the min from R, G, and B.
3. Take the average of all three.
4. Use some weighted average as others have suggested here.