Abstract

Color specifications for the official glass color standards of the U. S. Department of Agriculture for extracted honey, maple sirup, sugarcane sirup, and sugarcane molasses are presented. These standards are used for rapid classification of samples according to chromaticity. The chromaticities of the standards are widely and irregularly spaced along the sugar products locus on the CIE chromaticity diagram. Continuous single-number scales for color used in the sugar industry are based either on absorption measurements at specified wavelengths or on small-difference colorimetry. The uniform color scale of “NBS units of sugar color,” proposed by Deitz and based on the Adams color-difference formula, is useful as presently formulated only for the lighter colors. In the present paper a greatly extended scale of uniform chromaticity, based on MacAdam’s data, is presented for application to solutions of sugar products. Loci of points on the CIE diagram differing from the achromatic point by 5, 10, 15, ⋯, 220 units of chromaticity difference are established, and their intersections with an average locus of sugar products are determined. Forty-five glass color standards having chromaticities close to these intersections and thus spaced 5 units apart on the scale are described. The number of MacAdam units of sugar chromaticity, ΔS, for a given sample can be estimated by three methods: by interpolation between the aforementioned loci on the CIE diagram, if the chromaticity coordinates of the sample are known; by visual comparison with the 45 glass standards of known ΔS; and by measuring absorbancy of the sample at 420, 560, or 720 mμ and referring to graphs relating absorbancy to ΔS, if turbidity is negligible.

© 1960 Optical Society of America

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References

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  1. T. R. Gillett, Principles of Sugar Technology, edited by P. Honig (Elsevier Publishing Company, New York, 1953), Chap. 8.
  2. T. R. Gillett and W. D. Heath, Anal. Chem. 26, 1780 (1954).
    [Crossref]
  3. Zerban, Sattler, and Martin, Anal. Chem. 23, 308 (1951).
    [Crossref]
  4. Zerban, Martin, Erb, and Sattler, Anal. Chem. 24, 168 (1952).
    [Crossref]
  5. V. R. Deitz, J. Research Natl. Bur. Standards,  57, 159 (1956).
    [Crossref]
  6. B. A. Brice and A. Turner, J. Opt. Soc. Am. 46, 293 (1956).
    [Crossref]
  7. Brice, Turner, and White, J. Assoc. Official Agric. Chem. 39, 919 (1956).
  8. “United States standards for grades of sugarcane sirup, effective April 16, 1957” (Agricultural Marketing Service, U. S. Department of Agriculture, Washington, D. C.).
  9. C. B. Broeg and C. F. Walton, Anal. Chem. 24, 832 (1952).
    [Crossref]
  10. “United States standards for grades of sugarcane molasses, effective November 16, 1959” (Agricultural Marketing Service, U. S. Department of Agriculture, Washington, D. C.).
  11. Deitz, Pennington, and Hoffman, J. Research Natl. Bur. Standards 49, 365 (1952).
    [Crossref]
  12. D. B. Judd, Color in Business, Science, and Industry (John Wiley & Sons, Inc., New York, 1952), pp. 224–277.
  13. D. L. MacAdam, J. Opt. Soc. Am. 33, 18 (1943).
    [Crossref]
  14. G. W. Ingle, , 6–10 (October, 1954).
  15. D. B. Judd, J. Opt. Soc. Am. 23, 359 (1933).
    [Crossref]
  16. B. A. Brice, J. Opt. Soc. Am. 30, 152 (1940).
    [Crossref]
  17. Judd, Plaza, and Belknap, J. Research Natl. Bur. Standards 44, 559 (1950).
    [Crossref]

1956 (3)

V. R. Deitz, J. Research Natl. Bur. Standards,  57, 159 (1956).
[Crossref]

B. A. Brice and A. Turner, J. Opt. Soc. Am. 46, 293 (1956).
[Crossref]

Brice, Turner, and White, J. Assoc. Official Agric. Chem. 39, 919 (1956).

1954 (1)

T. R. Gillett and W. D. Heath, Anal. Chem. 26, 1780 (1954).
[Crossref]

1952 (3)

Zerban, Martin, Erb, and Sattler, Anal. Chem. 24, 168 (1952).
[Crossref]

C. B. Broeg and C. F. Walton, Anal. Chem. 24, 832 (1952).
[Crossref]

Deitz, Pennington, and Hoffman, J. Research Natl. Bur. Standards 49, 365 (1952).
[Crossref]

1951 (1)

Zerban, Sattler, and Martin, Anal. Chem. 23, 308 (1951).
[Crossref]

1950 (1)

Judd, Plaza, and Belknap, J. Research Natl. Bur. Standards 44, 559 (1950).
[Crossref]

1943 (1)

1940 (1)

1933 (1)

Belknap,

Judd, Plaza, and Belknap, J. Research Natl. Bur. Standards 44, 559 (1950).
[Crossref]

Brice,

Brice, Turner, and White, J. Assoc. Official Agric. Chem. 39, 919 (1956).

Brice, B. A.

Broeg, C. B.

C. B. Broeg and C. F. Walton, Anal. Chem. 24, 832 (1952).
[Crossref]

Deitz,

Deitz, Pennington, and Hoffman, J. Research Natl. Bur. Standards 49, 365 (1952).
[Crossref]

Deitz, V. R.

V. R. Deitz, J. Research Natl. Bur. Standards,  57, 159 (1956).
[Crossref]

Erb,

Zerban, Martin, Erb, and Sattler, Anal. Chem. 24, 168 (1952).
[Crossref]

Gillett, T. R.

T. R. Gillett and W. D. Heath, Anal. Chem. 26, 1780 (1954).
[Crossref]

T. R. Gillett, Principles of Sugar Technology, edited by P. Honig (Elsevier Publishing Company, New York, 1953), Chap. 8.

Heath, W. D.

T. R. Gillett and W. D. Heath, Anal. Chem. 26, 1780 (1954).
[Crossref]

Hoffman,

Deitz, Pennington, and Hoffman, J. Research Natl. Bur. Standards 49, 365 (1952).
[Crossref]

Ingle, G. W.

G. W. Ingle, , 6–10 (October, 1954).

Judd,

Judd, Plaza, and Belknap, J. Research Natl. Bur. Standards 44, 559 (1950).
[Crossref]

Judd, D. B.

D. B. Judd, J. Opt. Soc. Am. 23, 359 (1933).
[Crossref]

D. B. Judd, Color in Business, Science, and Industry (John Wiley & Sons, Inc., New York, 1952), pp. 224–277.

MacAdam, D. L.

Martin,

Zerban, Martin, Erb, and Sattler, Anal. Chem. 24, 168 (1952).
[Crossref]

Zerban, Sattler, and Martin, Anal. Chem. 23, 308 (1951).
[Crossref]

Pennington,

Deitz, Pennington, and Hoffman, J. Research Natl. Bur. Standards 49, 365 (1952).
[Crossref]

Plaza,

Judd, Plaza, and Belknap, J. Research Natl. Bur. Standards 44, 559 (1950).
[Crossref]

Sattler,

Zerban, Martin, Erb, and Sattler, Anal. Chem. 24, 168 (1952).
[Crossref]

Zerban, Sattler, and Martin, Anal. Chem. 23, 308 (1951).
[Crossref]

Turner,

Brice, Turner, and White, J. Assoc. Official Agric. Chem. 39, 919 (1956).

Turner, A.

Walton, C. F.

C. B. Broeg and C. F. Walton, Anal. Chem. 24, 832 (1952).
[Crossref]

White,

Brice, Turner, and White, J. Assoc. Official Agric. Chem. 39, 919 (1956).

Zerban,

Zerban, Martin, Erb, and Sattler, Anal. Chem. 24, 168 (1952).
[Crossref]

Zerban, Sattler, and Martin, Anal. Chem. 23, 308 (1951).
[Crossref]

Anal. Chem. (4)

T. R. Gillett and W. D. Heath, Anal. Chem. 26, 1780 (1954).
[Crossref]

Zerban, Sattler, and Martin, Anal. Chem. 23, 308 (1951).
[Crossref]

Zerban, Martin, Erb, and Sattler, Anal. Chem. 24, 168 (1952).
[Crossref]

C. B. Broeg and C. F. Walton, Anal. Chem. 24, 832 (1952).
[Crossref]

J. Assoc. Official Agric. Chem. (1)

Brice, Turner, and White, J. Assoc. Official Agric. Chem. 39, 919 (1956).

J. Opt. Soc. Am. (4)

J. Research Natl. Bur. Standards (3)

Judd, Plaza, and Belknap, J. Research Natl. Bur. Standards 44, 559 (1950).
[Crossref]

Deitz, Pennington, and Hoffman, J. Research Natl. Bur. Standards 49, 365 (1952).
[Crossref]

V. R. Deitz, J. Research Natl. Bur. Standards,  57, 159 (1956).
[Crossref]

Other (5)

T. R. Gillett, Principles of Sugar Technology, edited by P. Honig (Elsevier Publishing Company, New York, 1953), Chap. 8.

“United States standards for grades of sugarcane sirup, effective April 16, 1957” (Agricultural Marketing Service, U. S. Department of Agriculture, Washington, D. C.).

D. B. Judd, Color in Business, Science, and Industry (John Wiley & Sons, Inc., New York, 1952), pp. 224–277.

“United States standards for grades of sugarcane molasses, effective November 16, 1959” (Agricultural Marketing Service, U. S. Department of Agriculture, Washington, D. C.).

G. W. Ingle, , 6–10 (October, 1954).

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Figures (4)

Fig. 1
Fig. 1

Color comparator for classification of sugarcane sirup, showing the three mounted glass standards and two samples in cells of internal thickness 1 8 in.

Fig. 2
Fig. 2

CIE chromaticity diagram, showing coordinates for samples of maple sirup 31.5 mm (●); extracted honey, 31.5 mm (△); caramel-glycerin solutions, 31.5 mm (○); liquid sugar, 100 mm (▲); the various USDA glass color standards for sugar products (+); and the average locus of chromaticities for sugar products.

Fig. 3
Fig. 3

Loci of points along lines of constant dominant wavelength that depart from “colorless” by 5, 10, 15, ⋯ 220 MacAdam units of chromaticity difference. The average locus of chromaticities of sugar products is also shown.

Fig. 4
Fig. 4

Relationship between absorbancy at selected wavelengths and MacAdam units of sugar chromaticity for solutions of sugar products having negligible turbidity.

Tables (4)

Tables Icon

Table I Specifications and colorimetric analysis of USDA glass color standards. CIE data are based on 1931 standard observer and Illuminant C.

Tables Icon

Table II Chromaticity coordinates of points, along lines of constant dominant wavelength, differing from the achromatic point by 5, 10, 15, ⋯ MacAdam units of chromaticity difference, ΔS.

Tables Icon

Table III Intersections of MacAdam 5× loci with average sugar products locus. Description of glass standards with chromaticity coordinates near the intersections.

Tables Icon

Table IV Comparison of NBS units of sugar color, ΔENBS, with MacAdam units of sugar chromaticity, ΔS. Comparisons are valid only for the lighter colors above the spacing.

Equations (3)

Equations on this page are rendered with MathJax. Learn more.

( Δ S ) 2 = g 11 ( Δ x ) 2 + 2 g 12 Δ x Δ y + g 22 ( Δ y ) 2 ,
Δ y = m Δ x ,
Δ x = Δ S / ( g 11 + 2 g 12 m + g 22 m 2 ) 1 2 .