LCH Luminance vs HSL Lightness

50% lightness in HSL is almost never 50% as humans see it; it's just 50% lightness in that color space. 50% lightness in LCH is built around human lightness perception. See the Pen by Adam Argyle ( @argyleink ) on CodePen . Try in Canary or Safari TP with color web experiments on This demo shows how wild HSL is.. 50% light yellow is perceptually 97% lightness!! That's a massive difference. And it will totally bite you when you go to measure color contrast It may look like LCH is muted, desaturated, etc. But remember, we asked for 50% lightness.. so they shouldn't be that exciting, it's a middle of the road color. This thread and demo showcases why LCH type color spaces should be your colorspace for manipulation.