Fast, simple – no wonder this is the go-to grayscale algorithm for rookie programmers. This formula generates a reasonably nice grayscale equivalent, and its simplicity makes it easy to implement and optimize (look-up tables work quite well). However, this formula is not without shortcomings – while fast and simple, it does a poor job of representing shades of gray relative to the way humans perceive luminosity (brightness). For that, we need something a bit more complex.
Method 2 – Correcting for the human eye (sometimes called “luma” or “luminance,” though such terminology isn’t really accurate)