In colorimetry, the Munsell color system is a color space that specifies colors based upon three color dimensions: hue, value (lightness), and chroma (color purity). It was produced by Professor Albert H. Munsell inside the first decade of the twentieth century and adopted by the USDA since the official color system for soil research from the 1930s.
Several earlier color order systems had placed colors in a three-dimensional color solid of just one form or another, but Munsell was the first to separate hue, value, and chroma into perceptually uniform and independent dimensions, and the man was the first one to systematically illustrate the colors in three-dimensional space. Munsell’s system, in particular the later renotations, is based on rigorous measurements of human subjects’ visual responses to color, putting it on a firm experimental scientific basis. As a result basis in human visual perception, Munsell’s system has outlasted its contemporary color models, and even though it really has been superseded for several uses by models such as CIELAB (L*a*b*) and CIECAM02, it is still in wide use today.
Munsell’s color sphere, 1900. Later, munsell soil color chart found that if hue, value, and chroma were to be kept perceptually uniform, achievable surface colors could stop being forced into a regular shape.
Three-dimensional representation from the 1943 Munsell renotations. Spot the irregularity in the shape in comparison to Munsell’s earlier color sphere, at left.
The device includes three independent dimensions which is often represented cylindrically in three dimensions as an irregular color solid: hue, measured by degrees around horizontal circles; chroma, measured radially outward from your neutral (gray) vertical axis; and value, measured vertically from (black) to 10 (white). Munsell determined the spacing of colors along these dimensions by using measurements of human visual responses. In each dimension, Munsell colors are as close to perceptually uniform as he may make them, making the resulting shape quite irregular. As Munsell explains:
Desire to fit a chosen contour, including the pyramid, cone, cylinder or cube, in conjunction with an absence of proper tests, has generated many distorted statements of color relations, and it also becomes evident, when physical measurement of pigment values and chromas is studied, that no regular contour will serve.
-?Albert H. Munsell, “A Pigment Color System and Notation”
Each horizontal circle Munsell divided into five principal hues: Red, Yellow, Green, Blue, and Purple, in addition to 5 intermediate hues (e.g., YR) halfway between adjacent principal hues. Each one of these 10 steps, with the named hue given number 5, is going to be broken into 10 sub-steps, to ensure that 100 hues are shown integer values. In practice, color charts conventionally specify 40 hues, in increments of 2.5, progressing as for example 10R to 2.5YR.
Two colors of equal value and chroma, on opposite sides of your hue circle, are complementary colors, and mix additively towards the neutral gray of the same value. The diagram below shows 40 evenly spaced Munsell hues, with complements vertically aligned.
Value, or lightness, varies vertically across the color solid, from black (value ) at the end, to white (value 10) at the very top.Neutral grays lie down the vertical axis between monochrome.
Several color solids before Munsell’s plotted luminosity from black at the base to white on the top, by using a gray gradient between the two, however these systems neglected to hold perceptual lightness constant across horizontal slices. Instead, they plotted fully saturated yellow (light), and fully saturated blue and purple (dark) across the equator.
Chroma, measured radially from the center of each slice, represents the “purity” of your color (related to saturation), with lower chroma being less pure (more washed out, like pastels). Remember that there is not any intrinsic upper limit to chroma. Different regions of colour space have different maximal chroma coordinates. As an example light yellow colors have significantly more potential chroma than light purples, as a result of nature from the eye and the physics of color stimuli. This resulted in an array of possible chroma levels-as much as the high 30s for many hue-value combinations (though it is not easy or impossible to help make physical objects in colors of the high chromas, and so they should not be reproduced on current computer displays). Vivid solid colors are in the plethora of approximately 8.
Be aware that the Munsell Book of Color contains more color samples than this chart for both 5PB and 5Y (particularly bright yellows, up to 5Y 8.5/14). However, they are not reproducible in the sRGB color space, that has a limited color gamut designed to match that of televisions and computer displays. Note as well that there 85dexupky no samples for values (pure black) and 10 (pure white), which can be theoretical limits not reachable in pigment, with no printed examples of value 1..
A color is fully specified by listing three of the numbers for hue, value, and chroma in that order. As an illustration, a purple of medium lightness and fairly saturated could be 5P 5/10 with 5P meaning colour in the middle of the purple hue band, 5/ meaning medium value (lightness), and a chroma of 10 (see swatch).
The notion of employing a three-dimensional color solid to represent all colors was developed through the 18th and 19th centuries. Several different shapes for this kind of solid were proposed, including: a double triangular pyramid by Tobias Mayer in 1758, just one triangular pyramid by Johann Heinrich Lambert in 1772, a sphere by Philipp Otto Runge in 1810, a hemisphere by Michel Eugène Chevreul in 1839, a cone by Hermann von Helmholtz in 1860, a tilted cube by William Benson in 1868, and a slanted double cone by August Kirschmann in 1895. These systems became progressively more sophisticated, with Kirschmann’s even recognizing the real difference in value between bright colors of numerous hues. But them all remained either purely theoretical or encountered practical problems in accommodating all colors. Furthermore, none was based upon any rigorous scientific measurement of human vision; before Munsell, your relationship between hue, value, and chroma had not been understood.
Albert Munsell, an artist and professor of art on the Massachusetts Normal Art School (now Massachusetts College of Art and Design, or MassArt), wanted to create a “rational approach to describe color” that could use decimal notation as an alternative to color names (which he felt were “foolish” and “misleading”), which he can use to instruct his students about color. He first started work on the machine in 1898 and published it entirely form in the Color Notation in 1905.
The initial embodiment in the system (the 1905 Atlas) had some deficiencies like a physical representation of the theoretical system. These were improved significantly from the 1929 Munsell Book of Color and thru an extensive combination of experiments carried out by the Optical Society of America within the 1940s causing the notations (sample definitions) to the modern Munsell Book of Color. Though several replacements to the Munsell system have been invented, building on Munsell’s foundational ideas-such as the Optical Society of America’s Uniform Color Scales, and also the International Commission on Illumination’s CIELAB and CIECAM02 color models-the Munsell technique is still widely used, by, and the like, ANSI to define skin and hair colors for forensic pathology, the USGS for matching soil colors, in prosthodontics during picking shades for dental restorations, and breweries for matching beer colors.