Munsell Resources

by Paul Centore

(last updated May 12, 2016)

Measurements of Munsell Books

Spectrophotometric measurements of reflectance spectra of Munsell books provide useful data for further analysis. Here are some publicly available sets of measurements. The first four are measurements of X-Rite's 1976 Munsell Book of Color, made by the University of Joensuu in 1988 or 1989. This article analyzes the Joensuu measurements, and compares them to more recent measurements.

  1. Robin Myers has posted an extensive spectral library online, including many measurements of Munsell samples. (The program SpectraShop is required for viewing the data.)
  2. This page contains the Joensuu measurements of the 1976 matte Munsell book, made with an acousto-optical tunable filter (AOTF).
  3. This page contains the Joensuu measurements of the 1976 matte Munsell book, made with a Perkin-Elmer Lambda 9 spectrophotometer.
  4. This page contains the Joensuu measurements of the 1976 glossy Munsell book, made with a Perkin-Elmer Lambda 18 spectrophotometer.
  5. This page contains the Joensuu measurements of 32 glossy Munsell chips, made with a Minolta CM-2002 spectrophotometer.
  6. This textfile contains spectrophotometric measurements of the reflectance spectra of Munsell samples in X-Rite's 2007 Munsell Book of Color (Glossy finish). The measurements were made in 2012 with a ColorMunki spectrophotometer. This file gives the DEs for the measurements, with respect to the 1943 renotation, and converts them into CIE coordinates for Illuminants C and D50.
  7. In 2012, measurements were made of 235 swatches in the 2nd edition of The New Munsell Student Color Set. Only standard Munsell colours (those that occur in the 1943 renotation) were measured. A ColorMunki spectrophotometer was used for the measurements. This textfile contains the measured reflectance spectra data.

Conversions between Munsell and CIE Coordinates

The Munsell and Kubelka-Munk Toolbox contains two Octave/MATLAB routines, MunsellToxyY.m and xyYtoMunsell.m, that convert between CIE and Munsell coordinates. Other tools are also available for converting between Munsell specifications and CIE coordinates:

  1. The Virtual Atlas, produced by the British company VCS Consulting, is available for free download. The option View: Colour Conversion produces an interface for converting between Munsell and CIE coordinates. (Set the tabs above the entry area to read "C," "1931," "Munsell Aim," and "CIE Yxy." Then enter a Munsell string into the entry area and press "Go!" to convert that Munsell string to CIE coordinates.) The algorithm behind this code is discussed in a 1990 paper (N. S. Smith, T. W. A. Whitfield, & T. J. Wiltshire, "A Colour Notation Conversion Program," COLOR Research and Application, Vol. 15, Number 6, December 1990, pp. 338-343). The original implementation was in Pascal; the current implementation is object-oriented.
  2. Here are some open-source C/C++ conversions routines.
  3. Here is a Munsell package for R, the open source statistics program.
  4. Jose Gama has started a port of the Munsell and Kubelka-Munk Toolbox to R.
  5. Psychtoolbox-3 is a set of open source routines that run in Matlab, so they should work in Octave as well. This toolbox is developed mainly at the University of Pennsylvania, where it is used for vision research. Currently, it has code to convert from Munsell to xyY, but not from xyY to Munsell.
  6. The open-source Colour Science for Python project aims to provide comprehensive colour science software, in the Python programming language. Conversions between Munsell notations and CIE coordinates are in the process of being ported from code in the Munsell and Kubelka-Munk toolbox.
  7. Wallkill color produces commercial software that can be used interactively to make Munsell conversions. For $9.95 (as of Jan. 8, 2012), one can buy a one-year license for the basic Wallkill program. In the basic program, Munsell specifications can be entered manually, one at a time, and converted to xyY coordinates, and vice versa. One glitch is that the program will terminate, and must be restarted, if the entered specification is outside the MacAdam limits. The Wallkill program runs only on Windows systems.
  8. BabelColor's Patch Tool is also commercial software that performs Munsell conversions.
  9. The X-Rite VS450 spectrophotometer measures a colour's reflectance spectrum, and will automatically convert it to Munsell coordinates.
  10. A 1987 paper (Frederick T. Simon & Judith A. Frost. "A New Method for the Conversion of CIE Colorimetric Data to Munsell Notations," COLOR Research and Application, Vol. 12, Number 5, 1987, pp. 256-260) implemented Munsell conversion code in Fortran, as part of a thesis project. This code could not be located.
  11. A 1980 paper (Michael R. Pointer. "The Gamut of Real Surface Colours," Color Research and Application, Vol. 5, Number 3, 1980, pp. 145-155) says, on p. 146, "These Munsell notation data were converted into CIE coordinates using an extrapolation program." The program is attributed to a personal communication from L.E. DeMarsh in 1977. This program could not be located.

Conversions between Munsell and RGB Systems

  1. Here is a helpful online discussion about the problem of converting Munsell specifications to RGB coordinates.
  2. The discussion above suggested this free software for Munsell conversions. It is helpful for visualization, but only runs on PCs.
  3. The article Conversions Between the Munsell and sRGB Colour Systems provides a technical discussion of the issue, and resulted in two files (one for going from Munsell to sRGB, and one for the opposite direction) in the The Munsell and Kubelka-Munk Toolbox: MunsellRenotationTosRGB.txt and sRGBToMunsell.txt.
  4. Timo Teichert has provided a useful spreadsheet, Munsell-to-RGB-Tables.xlsm (or Munsell-to-RGB-Tables.xlsx), that visually implements the data in the two text files above.

Other Open-Source Octave/MATLAB Colour Science Code

In addition to the Munsell and Kubelka-Munk Toolbox, other open-source Octave/MATLAB code is available for colour science applications:

  1. Colorlab is a project started at the University of Valencia. Though it seems to be maintained sporadically, it a useful source of code, most of it fairly well documented.
  2. Psychtoolbox-3 is a set of open source routines that run in Matlab, so they should work in Octave as well. This toolbox is developed mainly at the University of Pennsylvania, where it is used for vision research. There is a forum, for which registration is required.
  3. Stephen Westland, Caterina Ripamonti, and Vien Cheung have produced their Computational Colour Toolbox, which is available at the MATLAB Central file exchange. Among other topics, there is code for colour appearance models, colour management, and colour device characterization.
  4. optprop is also availabe at the MATLAB Central file exchange. This toolbox uses sophisticated methods of representing and passing colour coordinates, and accessing basic illuminant and colour-matching data. Many of its graphics are three-dimensional. While three-dimensional graphics work well in MATLAB, Octave's three-dimensional capabilities are very limited, so not all the code will transfer to Octave.

    1. If anybody else knows of more resources, either for conversions, measurements of Munsell products, or open-source colour science code, please let me know at {centore ATSIGN}, and they will be added to the lists. Also, anybody is welcome to combine the open-source code listed above into a more unified and useful form.

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