It is immediately noticeable that HSL and HSV do not degrade at constant lightness, nor provide constant chroma or “saturation”. For the HSL/HSV models, since luminance and chroma are not defined, S and L/V have been roughly adjusted visually to match the perceptual gradients. The “saturation” as defined by the HSL space has been proven times and times again to hold no perceptual meaning and finds its origin into the first GUI of limited computers doing integer arithmetic. We can show here another illustration as to why HSL/HSV are meaningless to computer graphics. The following gradients where generated at constant CIE 1931 luminance $Y = 0.4075$ and at constant chroma. For each color model, the chroma has been empirically adjusted to the maximum value that produces a gradient fully contained within sRGB gamut (without clipping).
#Darktable import rotation wrong software
The saturation control of pretty much all image processing software is an unfortunate misnomer, to say the least. It actually controls either the chroma in Ych-like spaces (computed from CIE Yxy 1931, Yuv or YCbCr spaces), or some remote idea of saturation as used by HSL spaces, which are essentially a polar rewriting of RGB coordinates (usually expressed in sRGB space). Flatening the model and planning for gamut mapping.Synthetic sweeps at improved hue constancy.Expressing synthetic colours from perceptual hue and chroma.Manipulating real colours at constant hue and chroma.Building a new perceptual color space for color correction.Rewriting Oklab as Brightness-Saturation system.