Color Order Systems: Munsell, NCS and the CIE
How to name a color without naming a device, and why two of the great systems disagree about what a color notation is for.
Short answer: a color order system arranges colors into a structure you can navigate and name, using physical samples viewed under specified conditions. Munsell organises by hue, value and chroma and aims for equal perceptual steps in every direction. The Natural Colour System organises by how much a color resembles six elementary colors and makes no claim of equal spacing at all. The CIE systems are different again: not an atlas of samples but a set of numbers computed from measurement. Each answers a different question, and picking the wrong one is why people get frustrated with all three.
The problem a color order system solves
Hex codes, ink recipes and screen values are all device instructions. They tell some machine what to do, and the color that results depends on that machine. That is fine inside one workflow and useless across a table. If a soil scientist, an architect and a fabric buyer need to agree on a color, none of them can use the other two's numbers.
The oldest working answer is an atlas: a physical book of painted samples, each with a name, arranged in a structure so you can find the one you want and describe where it sits. You hold the sample against the thing, you find the closest match, and you read off the notation. The notation is not device dependent because the reference is a physical object, not a signal.
Munsell: three dimensions, deliberately separated
Albert Munsell's contribution was to split color into three attributes that vary independently, which sounds obvious now and was not at the time.
| Dimension | What it means | Scale |
|---|---|---|
| Hue | Which family the color belongs to | Ten families in a circle, each divided into ten steps |
| Value | How light or dark it is | 0 for ideal black to 10 for ideal white |
| Chroma | How far it is from a neutral grey of the same value | Open ended; the maximum depends on the hue and on what pigments exist |
A notation such as 5R 4/14 reads as hue 5R, value 4, chroma 14. The three parts are separable, which is exactly the property our page on hue, saturation and lightness is about, and the reason the system has survived for more than a century of use in fields as unlike each other as geology and interior design.
The open-ended chroma axis is the part that surprises people. There is no fixed maximum, because the maximum is a fact about available colorants rather than about perception. That makes the solid an irregular lump rather than a tidy sphere, and Munsell chose the irregular lump because it is honest.
The renotation, and why 1943 matters
The Munsell system as used today is not quite the one Munsell published. In 1943 a subcommittee of the Optical Society of America reported the results of a long program of visual measurement and produced a respacing of the system, so that the steps were as visually uniform as the data allowed. That report is the reason a modern Munsell notation can be converted to and from CIE coordinates: the renotation tied the atlas to colorimetric measurement.
The work continued afterwards. Very dark colors were poorly served by the original data, and an extension published in 1956 filled that region in. The pattern is worth noticing, because it recurs everywhere in color science: a system built on judgement gets tested against measurement, and the measurement sends you back to fix the regions where judgement was thin. The same story runs through color difference and Delta-E.
NCS: resemblance rather than spacing
The Natural Colour System, formalised as a Swedish standard and described in the color science literature in 1981, starts from a different premise. It is built on the observation, going back to Hering, that people describe colors by their resemblance to six elementary percepts: white, black, yellow, red, blue and green.
An NCS notation says how black a color looks, how chromatic it looks, and where its hue sits between two neighbouring elementary hues. Crucially, it does not claim that equal notation steps are equal perceptual steps. It claims to describe appearance, and it leaves uniformity out of the contract.
| Munsell | NCS | CIE (CIELAB and successors) | |
|---|---|---|---|
| Built from | Visual scaling experiments | Judgements of resemblance to elementary colors | Colorimetric measurement and modelling |
| Promises | Equal perceptual steps | Faithful description of appearance | Computable coordinates and difference formulas |
| Physical form | Atlas of painted samples | Atlas of painted samples | No samples; numbers from a spectrophotometer |
| Best at | Comparing and interpolating between colors | Communicating what a color looks like | Tolerances, quality control, conversion |
A 1990 comparison put Munsell, NCS, DIN and Coloroid side by side and found, unsurprisingly, that the systems differ in ways that follow from what each was designed to promise. Earlier work in 1985 set out the perceptual factors that constrain any such system, including the awkward fact that the appearance of a sample depends on the light it is under and on what surrounds it, so an atlas is only meaningful together with its viewing conditions.
Why the viewing conditions are part of the system
An atlas is a set of surfaces, and a surface has no color until light falls on it. Change the illuminant and the samples change, sometimes unequally, which is metamerism doing its usual damage. This is why colour order systems specify the light you are supposed to use, and why a match made under a shop's lighting fails in daylight.
It is also why the surround matters. Put a sample against white and against black and it will not look the same, an effect covered on our simultaneous contrast page. Serious atlas use involves a neutral grey mask with a hole in it, which sounds fussy until you have watched a match fall apart because of the page it was lying on.
Which one should you use
Use Munsell when you need to compare colors and reason about the steps between them: choosing a series, matching a specimen, teaching the three dimensions. Its perceptual spacing is the whole point.
Use NCS when the job is communication: telling someone what a color looks like in words that map onto how people actually talk about color. Architecture and paint specification lean this way for a reason.
Use CIE coordinates when you need arithmetic: tolerances, conversions, automated checks, anything a machine has to decide. The atlases cannot do this, and the numbers cannot tell you what the color looks like.
The three are not rivals so much as different tools, and most serious color work uses at least two of them. The digital descendants of the CIE line are covered on our OKLCH page, and the device side of the same problem on color management and ICC profiles.
The connection to the games
The best known Munsell-derived assessment arranges caps by hue and asks you to put them in order, which is why our page on the Farnsworth-Munsell 100 hue test exists. That test is a clinical instrument with controlled lighting and standardised scoring, and a browser game is not one.
What a game can do is train the underlying judgement. Huewheel asks you to find complements, analogous sets and triads on a hue circle, which is the Munsell hue dimension isolated from the other two. Doing that without a color picker is a genuinely different experience from reading about it, and it makes the arbitrariness of any particular wheel obvious: rotate 180 degrees in one system and in another and you do not land on the same color, a point taken up on color wheel relationships.
The hue dimension, on its own. Huewheel asks for complements, analogous sets and triads by eye. It is the Munsell hue circle turned into a task.
Frequently asked questions
What is a colour order system?
A structured arrangement of colours, usually realised as an atlas of physical samples, with a notation that lets you say where a colour sits in that structure. Because the reference is an object rather than a signal, two people in different places can agree on what a notation means.
What do the three numbers in a Munsell notation mean?
Hue, value and chroma. Hue is which family the colour belongs to, chosen from ten families each divided into ten steps. Value runs from 0 for ideal black to 10 for ideal white. Chroma measures distance from a neutral grey of the same value, and it has no fixed maximum.
Why does Munsell chroma have no upper limit?
Because the limit is a fact about available colorants, not about perception. Some hues can be pushed much further from neutral than others, so the colour solid is an irregular shape rather than a sphere. Munsell chose to keep the irregularity rather than force a tidy geometry.
What was the 1943 renotation?
A respacing of the Munsell system by a subcommittee of the Optical Society of America, based on a large programme of visual measurement. It made the steps as visually uniform as the data allowed and tied the atlas to CIE colorimetry, which is why modern Munsell notations can be converted to measured coordinates.
How is NCS different from Munsell?
Different promise. Munsell aims for equal perceptual steps in every direction. NCS describes how much a colour resembles six elementary percepts, white, black, yellow, red, blue and green, and explicitly does not claim that equal notation steps are equal perceptual steps.
Do I still need an atlas if I have CIELAB numbers?
They do different jobs. Measured coordinates give you arithmetic: tolerances, conversions, automatic checks. An atlas gives you a physical thing you can hold against a physical object, which is what you need when the object is a soil sample, a fabric or a wall.
Why do colour order systems specify the lighting?
Because a sample has no colour until light falls on it, and different illuminants change different samples by different amounts. The specified light is part of the system, not a nicety. A match made under shop lighting that fails in daylight is metamerism, not carelessness.
Is Huewheel a Munsell test?
No. It is a game that isolates the hue dimension and asks you to find relationships by eye. Clinical arrangement tests derived from the Munsell system use controlled lighting, standardised samples and validated scoring, none of which a browser can provide.
Keep reading
- Hue, saturation and lightness: the three dimensions, in the digital form.
- The Farnsworth-Munsell 100 hue test: what the arrangement test measures.
- Color difference and Delta-E: putting a number on how far apart two colors are.
Sources: Newhall, S. M., Nickerson, D. and Judd, D. B. (1943), Final report of the O.S.A. subcommittee on the spacing of the Munsell colors, Journal of the Optical Society of America 33(7), 385; Newhall, S. M. (1940), Preliminary report of the O.S.A. subcommittee on the spacing of the Munsell colors, Journal of the Optical Society of America 30(12), 617; Judd, D. B. and Wyszecki, G. (1956), Extension of the Munsell renotation system to very dark colors, Journal of the Optical Society of America 46(4), 281; Hård, A. and Sivik, L. (1981), NCS, Natural Color System: a Swedish standard for color notation, Color Research & Application 6(3), 129; Smith, N. S., Whitfield, T. W. A. and Wiltshire, T. J. (1990), A comparison of the Munsell, NCS, DIN and Coloroid colour order systems using paired comparisons, Color Research & Application 15(6), 327; Hunt, R. W. G. (1985), Perceptual factors affecting colour order systems, Color Research & Application 10(1), 12; Munsell Color, How colour notation works; International Commission on Illumination, CIE 015:2018 Colorimetry, 4th edition; MacEvoy, B., Colormaking attributes.
Understand it, now train it. The daily games stay free forever. A Personal Pass adds progress tracking (trends + export); Teacher / School tools let you assign it and follow a whole class. For teachers & self-learners →