Goal of the softwares GammaAdjuster (GA) and Output Linearization (OL)
The goal of both software tools is the equally spaced visual display output for equally spaced rgb* data in the file according to IEC 61966-2-1 (sRGB colour space). For applications the ergonomic standard ISO 9241-306:2018 defines 9 step achromatic and chromatic colour scales, download ISO-test charts AE49 of
https://standards.iso.org/iso/9241/306/ed-2/index.html
The output quality is specified by the regularity index g* according to ISO/IEC 15775:2022, download the ISO-test charts https://standards.iso.org/iso-iec/15775/ed-2/en
The regularity index g* depends on colour differences DE*ab in the colour space CIELAB. It is valid g*=100 (DE*min / DE*max). If the eight colour differences DE*ab of the nine step series are equal, then g*=100. If two steps are not distinguishable, then g*=0.
The visual output spacing is mainly changed by the display reflection of the ambient light. This change is known as gamma change and is described by a power function.
Software GammaAdjuster (GA, rgb*-colour management for the consumer area)
The software GammaAdjuster is a useful tool for changing the gamma value of the whole display output. A special Gamma value is determined, which produces approximately an equally spaced visual display output. The change is possible for three rgb* values together or individually for r*, g*, and b*.
The original gamma value is automatically restored by macOS when you exit the software.
Remark: The software GA corrects the values 0 <= rgb*=w* <= 1 by a power function, for example by w=w*0,5, if the too dark actual output has been produced by the inverse function w=w*2.
Software Output Linearization (OL, rgb *-color management for the professional area)
The software Output Linearization is a useful tool for producing the visual output of many 9 step colour series of a test file. The software OL may produce one individual function w=f(w*) for the achromatic series Black N - White W. In many cases this individual function produces also an approximately equally spaced display output for 12 other chromatic series.
Download now (version for SDR, requires macOS 13 or newer)
Download now (version for HDR, requires macOS 14 or newer)
Colour series N-W, N-RGBCMY, and RGBCMY-W and different viewing parameters.
The individual function of any series depends on many viewing parameters, for example adaptation luminance, and adjacent or separated samples.
Remark: For professional and research applications of rgb* colour management, see for example a paper of K. Richter (2025, 2,6 MB, 23 pages)
https://color.li.tu-berlin.de/tubws25e.pdf