This website is devoted to applying colour science to everyday problems that painters face. The goal is to provide, as far as possible, a rigorous understanding of the use of colour in painting. Although justifications for the results can be highly technical, the results are presented non-technically wherever possible, with an eye to practical employment by artists. An important tool is the Munsell Colour System, devised by the painter Albert Munsell at the turn of the 20th century. The Munsell system's concepts of hue, value, and chroma, are basic to painting, and provide a convenient framework for colour decisions in painting.
To use the Munsell system effectively, painters need printed exemplifications.
Currently available Munsell books are either of limited gamut,
or of high price. To remedy this situation, a Munsell home printing project was initiated,
described in
How To Print A Munsell Book. The
project produced Controlling
Colour with the Munsell System, a wide-gamut Munsell book
available for $75 on Amazon.com. A
picture of the book is shown below, and here is
a comparison with other
Munsell books.
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Value scales, or grey scales, that show how light or dark a colour is, are helpful for
artists and designers (and quilters, too). The scale pictured below is the result of a project
to produce an economical, finely gradated, Munsell-accurate tool to identify the Munsell values of
colours and to mix paints of a desired lightness. It is
available on Ebay.com
for $10.
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A scientific analysis of the colours of an object in shadow, relative to the colours of that same object in light, has led to two simple tools that realistic painters can use when depicting shadows. The first is a simple visual rule, expressed in terms of the Munsell system, and illustrated on the left. A PDF file with a detailed, non-technical explanation and examples, Shadow Colours For Painters, can be downloaded. The second tool appears in Consistent Shadow Values For Painters, which presents the visual aid shown below on the right. Painters can use this aid when representing objects of different colours in the same illumination.
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| An Example of Shadow Colours in the Munsell System | Visual Aid for Consistent Shadow Values |
Most pastel companies produce hundreds of pastels, of different colours. Painters need some organizational system, and some measured data, to use pastels effectively. This need is particularly acute when buying pastels sight unseen, because electronic and catalogue reproductions of pastels' colours are usually inaccurate. The page Colour Analysis of Pastels presents such results for eight pastel brands, in the reports Pastels: A Colour Guide For Artists and Manufacturers. A more technical discussion of the pastel gamut is given in A Colour Survey of Artist's Pastels. One interesting result is the discovery of duplicates, or pastels of the same brand whose colours are nearly identical. The figure below shows some duplicates for Rembrandt pastels.
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| Some Duplicates in Rembrandt Pastels |
Since many colour examples and discussions occur over the internet, it is helpful to
have a method for producing Munsell colours electronically. The sRGB system is a
colour standard for computer monitors and other display devices. When an
sRGB-compliant device uses an RGB triple to display a colour, the properties of
that colour conform to a colorimetric, device-independent specification. As a
result, the same RGB triple should always produce the same colour, even
though it is displayed on
different sRGB-compliant devices. The Munsell system also conforms to a
colorimetric specification, called the Munsell Renotation. Both systems specify
ambient lighting conditions for viewing, but the sRGB system uses Illuminant D65 lighting,
while the Munsell system uses Illuminant C lighting. The article
Conversions Between the Munsell and sRGB Colour Systems provides a set of
tables that specify which sRGB values produce desired Munsell
colours on a computer monitor. To account for the differences between Illuminants
C and D65, the monitor should be viewed in a
room lit by indirect daylight.
Comments, criticisms, suggestions, and questions are welcomed on any of the topics covered by this website. I can be reached by email at xxxpaul@xxxisletech.xxxnet (leave the x's out of the address).
Though this site presents easily applied, and therefore non-technical, procedures for painters, the procedures have highly technical origins. Much of the development relied on Octave/MATLAB computer code written by myself, and assembled into the open-source Munsell and Kubelka-Munk Toolbox. Other researchers are invited to correct, modify, and extend this code, with the understanding that they will make their modifications and extensions freely available. The process of developing tools for artists led into many aspects of colour science. The page Colour Science Papers presents some peer-reviewed publications that resulted, along with more expository writings.