Generalized Hyperbolic Stretch

Software RawTherapee
54

I’ve made a number of improvements to GHS.

Modes:

  • RGB Luminance and standard RGB modes now take stretch into account to adjust saturation.
  • Luminance & Chromaticity (Lab) mode takes chromaticity directly into account - which can be adjusted. This mode requires different settings for “D” , “b”, “SP”.

Settings SP, etc. :
It’s easier to set “SP” now that the histogram, when you click on the icon of the gamut button Gamut-hist.png, displays the data corresponding to those used in the algorithm: working profile and gamma=1

First image with “Histogram and Navigator panel” taking into account Output profile

image
image1911×484 215 KB

Second image with “Histogram and Navigator panel” taking into account Working profile and gamma=1

image
image1916×530 261 KB

GHS function representation

  • now when you click on “Linear” the system is reset
  • but it’s still not perfect. It’s not a curve, just a help

Executables
ghs