There are more formulas to be used, depending on the source material: https://en.wikipedia.org/wiki/Grayscale#Luma_coding_in_video_systems https://en.wikipedia.

There are more formulas to be used, depending on the source material: https://en.wikipedia.org/wiki/Grayscale#Luma_coding_in_video_systems https://en.wikipedia.org/wiki/Grayscale#Luma_coding_in_video...