Instead, they plotted fully saturated yellow (light), and fully saturated blue and purple (dark) along the equator.Ĭhroma, measured radially from the center of each slice, represents the “purity” of a color (related to saturation), with lower chroma being less pure (more washed out, as in pastels). Several color solids before Munsell's plotted luminosity from black on the bottom to white on the top, with a gray gradient between them, but these systems neglected to keep perceptual lightness constant across horizontal slices. Neutral grays lie along the vertical axis between black and white. Value, or lightness, varies vertically along the color solid, from black (value 0) at the bottom, to white (value 10) at the top. As Munsell explains:ĭesire to fit a chosen contour, such as the pyramid, cone, cylinder or cube, coupled with a lack of proper tests, has led to many distorted statements of color relations, and it becomes evident, when physical measurement of pigment values and chromas is studied, that no regular contour will serve. In each dimension, Munsell colors are as close to perceptually uniform as he could make them, which makes the resulting shape quite irregular. Munsell determined the spacing of colors along these dimensions by taking measurements of human visual responses. value, measured vertically on the core cylinder from 0 (black) to 10 (white).chroma, measured radially outward from the neutral (gray) vertical axis.hue, measured by degrees around horizontal circles.The system consists of three independent properties of color which can be represented cylindrically in three dimensions as an irregular color solid: Notice the irregularity of the shape when compared with Munsell's earlier color sphere. Three-dimensional representation of the 1943 Munsell renotations (with portion cut away). Because of this basis in human visual perception, Munsell's system has outlasted its contemporary color models, and though it has been superseded for some uses by models such as CIELAB ( L*a*b*) and CIECAM02, it is still in wide use today. Munsell's system, particularly the later renotations, is based on rigorous measurements of human subjects' visual responses to color, putting it on a firm experimental scientific basis. Several earlier color order systems had placed colors into a three-dimensional color solid of one form or another, but Munsell was the first to separate hue, value, and chroma into perceptually uniform and independent dimensions, and he was the first to illustrate the colors systematically in three-dimensional space. Munsell in the first decade of the 20th century and adopted by the United States Department of Agriculture (USDA) as the official color system for soil research in the 1930s. In colorimetry, the Munsell color system is a color space that specifies colors based on three properties of color: hue (basic color), chroma (color intensity), and value ( lightness). Then you need to provide more clues or experiment more with what that command does in GIMP - or provide examples.The Munsell color system, showing: a circle of hues at value 5 chroma 6 the neutral values from 0 to 10 and the chromas of purple-blue (5PB) at value 5. You then want to do something ? to affect the Chroma channel, so try -auto-level for now, and then return to sRGB colourspace and save: magick INPUT.PNG -colorspace HCL -channel G -auto-level +channel -colorspace sRGB RESULT.PNG

I don't know what that command does in GIMP, but you can convert to HCL colourspace in ImageMagick and select the Chroma channel for modification like this: magick INPUT.PNG -colorspace HCL -channel G. Then you go back to ImageMagick and apply that CLUT to your image: magick input.png GIMP-H0-C50-L0.png -hald-clut result.pngĪnd I think you'll agree the left side looks pretty similar to the right side of your input image. Then take that file ( clut.png) into GIMP and apply your GIMP processing on it and save the result as GIMP-H0-C50-L0.png so we know how GIMP affects each colour. You would create a HALD-CLUT something like this: magick hald:16 clut.png The method below should allow you to replicate any GIMP filter with ImageMagick - as long as it is a pure 'point process', I mean one where each pixel's output value is purely derived from its input value and not an 'area process' where surrounding pixels contribute - such as blurring or median filtering, for example. If that doesn't work, or is not to your liking, read on. I got: magick cXDv3.jpg -define modulate:colorspace=LCH -modulate 100,150 result.jpg I think you can get pretty close with -modulate if you go into an LCH colourspace, but I have no idea if it will work consistently.

Chroma for hue