The Ostwald system creates a color space based on dominant wavelength, purity, and luminance, mapping the values of hue, saturation and brightness. Establishing the values for these parameters is done with a disc colorimeter which mixes on a disk amounts of the pure spectral color at the dominant wavelength with white, and black . Thus the point in the Ostwald color space is represented by values C,W, and B to represent the percentages of the circle. For example 35,15,50 represents 35% full color, 15% white, and 50% black.
The OSTWALD system is based upon an analysis of reflectance curves.
The word "harmony" in the title aptly symbolizes what Ostwald wanted to achieve with colors. Experience had shown him (and others) that some color combinations could be seen as pleasant (or harmonious), while others were unpleasant. The question was why, and whether a law could be formulated. With his analysis of color-harmony, Ostwald proceeds on the basis of his conviction that harmony is created by color-order. A double-cone is put forward with one white and one black tip between which a stepped grey-scale is arranged, modeled according to a fundamental psychological law. The double-cone extends from a color-circle divided into 24 segments (the full colors) which in turn stem from the four proto-colors of yellow, red, blue and sea-green
His Farbfibel "The color primer" (historical illustr. 1; illustr. 2; illustr. 3), which appeared in 1916, introduced a color system devoted to this task (and survived for 15 editions).
Ostwald, who had met Albert H. Munsell in 1905 on a journey to America, attempted to devise a system — just as the American painter had done — based on perception and equalizing the respective differences between individual colors. Expressed in our modern technical language, we can say that Ostwald attempted to construct a perceptual color-system using non-empirical methods. In place of Munsell's three parameters, he selected an alternative group of variables: namely, color-content, white-content and black-content. He also introduced the special term "full color", by which he meant a color which permitted the sensation of one single color-tone (Munsell's "hue") and was not tempered by white or black. To be more accurate, we could say that a full color is an optimally pure color — in other words, of maximum saturation and at the same time bright. Full colors are, of course, ideal colors which cannot be reproduced by actual pigments. (When Ostwald published his Color Primer, his full colors contained about 5% white and slightly less black, as he himself admitted.)
We can thus formulate the guiding principle behind Ostwald's theory of color in the following way: the most universal mixture is the mixture of full colors, white and black. Each pigmented color can be characterized by specifying the color-content (at a certain color-hue), white-content and black-content. In his Farbfibel, Ostwald proceeds systematically, drawing a distinction between chromatic and achromatic colors. He arranges his achromatic colors in the form of a grey scale along a line containing eight gradations, which conform to a geometrical sequence. In other words, the influence of visually dominant white does not decrease uniformly from above downwards, but does so geometrically, with the perceived mid-point between black and white being characterised by a proportion of approximately 20% white. (To avoid confusion, we have omitted the letters used here by Ostwald to identify these gradations.) The basis of the sequence is the so-called Weber-Fechner Law of Psychophysiology, although its application is technically limited. In fact, Ostwald abandoned his grey sequence which used this law as a basis.
The full colors are arranged around a complete circle which leans towards Hering's system and starts out with four basic colors: yellow to the north; red to the east; blue (to be more exact, ultramarine) to the south; and sea-green to the west. Four further colors are then placed between these: orange between yellow and red; violet between red and ultramarine blue; turquoise between ultramarine blue and sea-green; and leaf-green between sea-green and yellow. (Ostwald names orange "kress" and violet "veil". At the time of World War I, it was considered prudent to avoid all words borrowed from the French. However, we shall not be doing so.) As with Munsell, the colors are arranged so that compensating colors (i.e. color-pairs whose mixtures produce a neutral grey) are placed opposite each other: yellow-ultramarine blue, orange-turquoise, red-sea-green, and violet-leaf green.
With these eight colors, Ostwald constructs 24 color-hues with equal spacing and numbers them from yellow upwards, arranging them into a circle.
From the full colors of this circle, Ostwald then constructs the so-called "bright-clear", or "dark-clear" colors, resulting in a series which, towards either white or black, is "perceptually equidistant" from each respective color. With that, Ostwald can proceed with the fulfillment of his original task: namely, to specify the general mixing of the other colors characterized by him as "dull colors" (or, in accordance with Hering, "veiled colors") and forming most of the colors existing in the color-solid.
Each such dull color can be defined from a mixture of a full color and a grey tone, with the grey tone being defined from a mixture of black and white. The color standard desired of any particular full color can therefore be realized using an equilateral triangle, with its central black-white axis — the grey scale — lying opposite the full color as the third point. The sides of the triangle running from the full color towards either black or white each contain "dark-clear" or "bright-clear" color sequences.
When joined onto the triangle of opposing complementary colors, such a monochromatic triangle — regarded as "psychological" by Ostwald — becomes a rhombus (below right) which can be applied to the entire circle of pure colours. The basis of a double-cone is created in this way, uniting all the colors of Ostwald's system (above right). The Color Harmony Manual, the third edition of which was published in 1948, provides a very good practical embodiment of this construction.
The word "harmony" in the title aptly symbolizes what Ostwald wanted to achieve with colors. Experience had shown him (and others) that some color combinations could be seen as pleasant (or harmonious), while others were unpleasant. The question was why, and whether a law could be formulated. With his analysis of color-harmony, Ostwald proceeds on the basis of his conviction that harmony is created by color-order. To identify these harmonies, he even drafted a law (harmony = order), claiming that he could find all harmonies by analyzing all the orders of color which his color solid — the double-cone — would allow, and that he could do this according to the rules of geometry. From 1926 onwards, these harmonies were summarized — initially by Ostwald himself — first of all in a Harmothek and later in the Color Harmony Manual, with which we are already familiar.
It would not be fitting for us to criticize Ostwald's theory of color, but it does appear that its effect is not very convincing. We probably have to accept that science does not provide us with information about the harmonious combination of colors in the same way as with sounds. Light and sound are different wave forms, and the eye, in contrast to the ear, possesses only rudimentary capabilities with regard to comparative analysis. In addition, we can barely see more than an octave (the maximum extent of the visible spectrum). There also appears to be no physical or physiological basis to the assumption that some individual combinations of color are more desirable than others. Nobody — including Ostwald — has ever thought of improving on the magnificence of a rainbow by removing or adding a component of its colors. However, Ostwald did wish to improve Japanese woodcuts and recommended a new coloring using his standards as a basis, henceforth regarding this to be more "Japanese" than the originals.
In the world of art, Ostwald may indeed have created rather a doubtful reputation for himself with this claim. But his system nevertheless left its mark: for example, the Dutch "De Stijl" movement with Piet Mondrian at its centre focused on his work — at any rate, Mondrian's treatment of colors in 1917 and 1918 had much in common with Ostwald's theories.