colorimetry Colorimetry is "the science and technology used to quantify and describe physically the human color perception". It is similar to spectrophotometry, but is distinguished by its interest in reducing spectra to the physical correlates of color ...

, the Ostwald color system is a

color space A color space is a specific organization of colors. In combination with color profiling supported by various physical devices, it supports reproducible representations of colorwhether such representation entails an analog or a digital representa ...

that was invented by the

Baltic German Baltic Germans (german: Deutsch-Balten or , later ) were ethnic German inhabitants of the eastern shores of the Baltic Sea, in what today are Estonia and Latvia. Since their coerced resettlement in 1939, Baltic Germans have markedly declined ...

chemist

Wilhelm Ostwald Friedrich Wilhelm Ostwald (; 4 April 1932) was a Baltic German chemist and philosopher. Ostwald is credited with being one of the founders of the field of physical chemistry, with Jacobus Henricus van 't Hoff, Walther Nernst, and Svante Arrh ...

. Associated wit
''The Color Harmony Manual''
it comprises a set of paint chips representing the Ostwald color space. There are four different editions of the ''Color Harmony Manual''. Each manual is made up of charts, with each chart being a different color space.

Ostwald

Ostwald recommended a systematic arrangement of colors and a standardization of colors used. Ostwald believed colors should only be used and selected from a finite collection. He acknowledged that his system left out some intermediate colors between the ones he selected, but he did not work to include them in his color space. Ostwald's system provides a single, midpoint

interpolation In the mathematical field of numerical analysis, interpolation is a type of estimation, a method of constructing (finding) new data points based on the range of a discrete set of known data points. In engineering and science, one often has ...

between adjacent colors. It does not have an easy way of recording millions of colors.

The charts

The ''Color Harmony Manual'' is made up of charts of colored chips representing a color space. The overall shape of a chart is an

equilateral triangle In geometry, an equilateral triangle is a triangle in which all three sides have the same length. In the familiar Euclidean geometry, an equilateral triangle is also equiangular; that is, all three internal angles are also congruent to each oth ...

made up of 28 samples. Each chart is made up of samples of approximately the same hue. Each chart has one sample with the greatest

purity Purity may refer to: Books * ''Pureza'' (novel), a 1937 Brazilian novel by José Lins do Rego * ''Purity'' (novel), a 2015 novel by Jonathan Franzen ** ''Purity'' (TV series), a TV series based on the novel *''Purity'', a 2012 novel by Jackson P ...

. This sample is the far point of the triangle. A series of five samples with increasing

reflectance The reflectance of the surface of a material is its effectiveness in Reflection (physics), reflecting radiant energy. It is the fraction of incident electromagnetic power that is reflected at the boundary. Reflectance is a component of the respon ...

and decreasing purity are on the upper edge of the triangle. It ends with an almost-gray modification of the original pure hue. A series of five samples with decreasing reflectance and decreasing purity are on the lower edge of the triangle. It ends with an almost-black modification of the original hue. Between these light and dark series are other samples of intermediate reflectance and purity. All color samples on the same chart have almost the same dominant

wavelength In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tr ...

. All color samples in the same vertical row have almost the same dominant wavelength and purity, making the only difference the reflectances. Color samples made from clear

cellulose acetate In biochemistry, cellulose acetate refers to any acetate ester of cellulose, usually cellulose diacetate. It was first prepared in 1865. A bioplastic, cellulose acetate is used as a film base in photography, as a component in some coatings, ...

sheets with one side coated with an opaque colored lacquer. This ensures that both sides are the same color while one side is

glossy Gloss is an optical property which indicates how well a surface reflects light in a specular (mirror-like) direction. It is one of the important parameters that are used to describe the visual appearance of an object. The factors that affect glo ...

and the other is matte.

History of editions

The ''Color Harmony Manuals'' were published beginning in 1942, and have been out of print since 1972. Ostwald's first ''Color Harmony Manual'' was a set of 12 handbooks showing complementary hues. The first edition was published in 1942. It contained 680 color chips. Each color chip was a 5/8 inch square and had a tab where the Ostwald notation was written. A ''Color Harmony Index'' was also produced. It used larger 1 inch square color chips. But, due to its price only a few were sold. In 1945, Walter C. Granville was asked to produce a second edition. The second edition used the chips from the ''Color Harmony Index'' but was formatted up the same way as the first edition. The second edition is also called the large chip edition. By 1948 all copies of both the first and second edition had sold. The third edition was published in February 1949. A different colorimetric base was used for the third edition, so the colors are approximate matches to the colors of the first and second editions. There was also a second production of the third edition to reuse batches of the liquors used to make the color chip stock. The fourth edition was published in 1958. It was sold until 1972. A different base lacquer formula was used in the fourth edition, and there was a substitute of some

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic comp ...

s, most notably in one of the

yellow Yellow is the color between green and orange on the spectrum of light. It is evoked by light with a dominant wavelength of roughly 575585 nm. It is a primary color in subtractive color systems, used in painting or color printing. In ...

s. In 1971, Granville was asked to compare the colors of the third and fourth editions. He found that the fourth edition did not meet the third edition's standards. Colors between the fourth edition did not match the colors of the first edition as closely as the third edition had. This was confirmed by W. N. Hale and the fourth edition was discontinued. The overproduction of color chips for the third and fourth editions lead to sales of individual chips.

The first and second editions

For the first and second editions, the color chips were made from the same stock. So the colors between these two editions are identical. Carl E. Foss made the chip stock using disc mixtures. A modification was needed to show the colors of maximum purity between the full color and white. The disc mixtures of the full color and white gave colors less saturated than the pigmented lacquers could. To fix this, Foss substituted the pigment for the disc mixture. This substitute included colors that would have been left out if the Ostwald color theory had been followed directly.

References

{{DEFAULTSORT:Ostwald Color System Color space