deltaE / Color Similarity masks - Do I understand correctly?

[agriggio (Alberto)]

Hi,
What I wrote is still true (except for the name that got changed to “color similarly” because deltaE is a bit too technical). In particular:

@lphilpot

L, C & H - These define the colors’ luminosity, chromaticity and hue ranges as bounded by the left and right sliders, per widget. Nothing outside these ranges is even considered for masking

That’s not how they work. For each bar, the top slider sets the anchor value (i.e. the specific value of lightness, chromaticity and hue of the anchor colour which you can also set with the picker). The bottom slider defines the weight of the channel in the computation of the deltaE (i.e. the “distance”) formula.
DeltaE is a sort of weighted Euclidean norm, something like this:

\sqrt{w_l * L^2 + w_c * C^2 + w_h * H^2}

The mask considers as similar those colors that are close to the target according to the above metric. Range controls the bounds for considering similar colors, decay controls the rate of the transition from similar to not similar. The three sliders set the weights and the L, C and H values.

HTH