Abstract
People have been conscious of color from the earliest times. Cave dwellers decorated their walls with coloring materials that they dug from the earth. Mineral colors, a few vegetable dyes, and some dyes obtained from insects and mollusks were the only materials available until the last century. The paucity of usable materials was not remedied until after Perkin’s synthesis of mauve from coal tar in 1856. That discovery led to the introduction of thousands of synthetic dyes and pigments. In the ever-increasing use of color today, the lack of suitable coloring materials no longer limits the variety of attainable colors.
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References
Chapters 1–3 and Sect. 4.1–3, 5.1–3 are abridgments (with revisions and additions) of text in the Handbook of Colorimetry, which was prepared by the staff of the Color Measurement Laboratory of the Massachusetts Institute of Technology under the direction of Professor Arthur C. Hardy. I participated in its preparation. The handbook was published in 1936 by The Technology Press. It is kept in print by the MIT Press. It contains extensive tables and charts that are uniquely useful, especially for colorimetry with the CIE 1931 color-matching data and illuminant C. The abridgments, Figs. 1.1–4.1, 5.1, and Tables 1.1–5.3, 5.6 have been revised and are included in this book by permission of the MIT Press.
For a discussion of operational definitions, see P. W. Bridgman: The Logic of Modern Physics (Macmillan, New York 1927).
Reflectance can depend on intensity of the incident beam in the case of photochromic materials, or when the intensity is so great that it burns or otherwise irreversibly changes the sample. Long periods of exposure to light can also cause irreversible changes of reflectance, which are usually referred to as fading. Fading is rarely encountered in modern spectrophotometric practice, because the measuring beams are not very intense. Fading is usually accelerated, or even occurs in the absence of light, by high temperatures and/or high humidity, or exposure to other vapors. Photochromic changes are temporary; the rapidity and magnitudes of photochromic changes and the time required for recovery from them are proportional to the intensity of the exposing beam. The intensities and durations of exposure to the measuring beams in modern spectrophotometers are so low and short that appreciable photochromic effects are rare in spectrophotometry of materials ordinarily encountered. Photochromic glass is used in some sunglasses, and in industrial and military goggles. Those sunglasses darken on continued exposure to sunlight. The goggles darken rapidly on exposure to extremely intense light, as from nuclear explosions or lasers. An increasingly common example of photochromic change of color occurs in house paint that contains the rutile variety of titanium dioxide. Normally, being exposed continually to daylight, the paint is an untinted white, but paint fresh out of the can has a more or less distinct ivory or cream tint. That tint fades or bleaches in daylight to the white. But storm sash stored in the dark may revert to the cream or ivory over the summer and exhibit a dismaying mismatch when reinstalled. A few days in daylight restores the match by photochromism. A more expensive variety of titanium dioxide, anatase, is always white; it is not photochromic.
For use in double-beam spectrophotometers, or for calibrating single-beam spectrophotometers, actual white materials are used as working standards. Around 1930, freshly scraped blocks of magnesium carbonate were used. Later, the fresh surface of such blocks was coated with a 1 or 2 mm-thick layer of magnesium oxide, deposited as smoke from freely burning metallic chips or ribbon of magnesium. More recently, such a layer of MgO deposited in a 2 mm cavity machined in an aluminum plate has been widely used, because it is more durable and has constant reflectance as high as MgO on MgCO3 throughout the visible spectrum. More durable and more easily prepared working standards of purified barium sulfate have also been used recently, in the form of disks prepared under pressure and a paint made with polyvinyl alcohol. A proprietary material named Halon® (Allied Chemical Corp.) has recently become available, with which very durable and high-reflectance working standards can be prepared very conveniently. Disks of beryllium oxide are available; they are extremely durable and easily cleaned to assure constant reflectance, although their reflectance is not quite so high as MgO, BaSO4, or Halon®. Whatever working standard is used should be calibrated by absolute reflectometry. Spectrophotometers determine the ratios of spectral reflectances of samples to the reflectance of the working standard. That ratio should be divided by the absolute reflectance of the working standard, to determine the absolute spectral reflectances of the sample. Because most laboratories lack means for determination of absolute reflectances of working standards, it is necessary to use very durable, accurately replaceable, and easily cleaned working standards of a type whose absolute reflectance has been determined in some standardizing laboratory, such as the US National Bureau of Standards, the National Physical Laboratory in Teddington, England, the National Research Council in Ottawa, Canada, or the Bundesanstalt für Materialprüfung in Berlin. Durability and precise interchangeability are more-desirable attributes of such working standards than highest-possible or constant reflectance. In the most-recent spectrophotometers, which incorporate computers, the absolute spectral reflectances can be stored and automatically divided into the measured ratios of the reflectances of samples and the working standard.
That a surface illuminated by a single wavelength will reflect light of only that wavelength is not true of fluorescent materials. In general, they also emit wavelengths longer than the illuminating wavelength. Such materials greatly complicate the concept and measurement of spectral reflectance. Those complications will not be discussed in this book. The problem is dealt with by F. Grum, C. J. Bartleson (eds.): Optical Radiation Measurements, Vol. 2: Color Measurements (Academic, New York 1980). Here, it is sufficient to state that the method presented in this book may be used to evaluate the color of the light received by the eye from any material, whether or not it is fluorescent.
The wavelengths indicated by the dashed vertical lines in Figs. 1.1–5 are the dominant wavelengths, which will be defined in Sect. 1.10. The dashed line in Fig. 1.6 indicates the complementary wavelength, which will also be defined in Sect. 1.10.
The initials (ICI) of the English translation of the name of the Commission Internationale de l’Eclairage are frequent in the literature of colorimetry from 1932 until about 1950. The initials (CIE) of the official French name have generally been used more recently, although IBK (the initials of the German name) and MKO (the initials of the Russian name) are still encountered. The initials CIE will be used in this book.
This account of the fundamental experiments of colorimetry is schematic and greatly simplified. It is valid in principle and adequate for this discussion. Complicating details of procedure and results, some of which will be mentioned later, are of more concern in relation to the psychology and physiology of color vision than for colorimetry.
J. C. Maxwell: On the theory of compound colors and the relations of the colours of the spectrum. Proc. Roy. Soc. London 10, 404, 484 (1860);
J. C. Maxwell: On the theory of compound colors and the relations of the colours of the spectrum. Phil. Mag. (4) 21, 141 (1860);
J. C. Maxwell: Scientific Papers (Cambridge Univ., Cambridge 1890) pp. 149, 410.
A. König, C. Dieterici: Die Grundempfindungen in normalen und anomalen Farbensystemen und ihre Intensitätsverteilungen im Spektrum. Z. Psychol. Physiol. Sinnesorg. 4, 231 (1892);
A. König: Gesammelte Abhandlungen (Barth, Leipzig 1903) p. 214.
W. deW. Abney: The colour sensations in terms of luminosity. Phil. Trans. Roy. Soc. London 193, 259 (1905).
L. T. Troland: Report of Committee on Colorimetry for 1920–21. J. Opt. Soc. Am. 6, 527–596 (1922).
W. D. Wright: A redetermination of the trichromatic coefficients of the spectral colours. Trans. Opt. Soc. London 30, 141–164 (1928–29).
J. Guild: The colorimetric properties of the spectrum. Phil. Trans. Roy. Soc. London A230, 149–187 (1931).
CIE Proceedings 1931 (Cambridge Univ., Cambridge 1932) p. 19.
W. S. Stiles, J. M. Burch: NPL colour-matching investigation, final report. Opt. Acta 6, 1–26 (1959).
N. I. Speranskaya: Determination of spectrum color coordinates for twenty-seven normal observers. Opt. Spectrosc. (USSR) 7, 424–428 (1959).
CIE Proceedings 1963, Bureau Central de la CIE, 52, Boulevard Malesherbes, 75008 Paris, France. If copies are available, they may be obtained from J. L. Tech. Secretary USNC/CIE, National Bureau of Standards, Washington, D.C. 20234.
Specification of hue in terms of wavelength is not strictly correct, as discussed in Sects. 5.2, 3. The wavelengths mentioned here are dominant wavelengths, which are defined in Sect. 1.10. In the present instances, the straight lines drawn from the white (illuminant C) point to the points on the spectrum locus of the wavelengths mentioned are extended beyond the spectrum locus to the points that represent the green and the blue primaries (at x = 0, y = 1 and x = y = 0, respectively). The “red” primary, at x = 1, y = 0 does not have a dominant wavelength. It has the complementary wavelength 496 nm.
Simultaneous color contrast is discussed in G. A. Agoston: Color Theory and Its Application in Art and Design, Springer Series in Optical Sciences, Vol. 19 (Springer, Berlin, Heidelberg, New York 1979) pp. 5, 61.
Gloss and other appearance characteristics are discussed by Richard S. Hunter: The Measurement of Appearance (Wiley, New York 1975).
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MacAdam, D.L. (1981). The Physical Basis of Color Specification. In: Color Measurement. Springer Series in Optical Sciences, vol 27. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-662-13508-2_1
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