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 connection with the work of the Newhall subcommittee (OSA Colorimetry Committee) on Review of Spacing of the Munsell Colors (10), (11). It was completed in order to make full information available to all color workers who may have use for any of the Munsell papers. The data for the 20 new hues, and the /2 chromas originally omitted in the 10 intermediates of the regular 20 hue series, are placed in order by hue in Table I. Data for half-value step and special neutrals are assembled in Table II. Data for other special series are placed together by title in Table III.

The authors are indebted to the Munsell Color Company for supplying samples and production numbers, and to their respective laboratories for permission to carry on and publish this work.

BIBLIOGRAPHY

(1) A. H. Munsell, A Color Notation (Munsell Color Company, Inc., Baltimore, Maryland, 1936), eighth edition, edited and rearranged. (2) Milton E. Bond and Dorothy Nickerson, ‘‘Color order systems, Ostwald and Munsell,” J. Opt. Soc. Am. 32, 709 (1942). (3) Dorothy Nickerson, ‘‘History of Munsell color system and its scientific application,” J. Opt. Soc. Am. 30, 575 (1940). (4) American Standards Association, American War Standard, Specification and Description of Color, Z44-1942 (June 17, 1942). (5) Munsell Book of Color (Munsell Color Company, Inc., Baltimore, Maryland, 1929). (6) J. J. Glenn and J. T. Killian, ‘‘Trichromatic analysis of the Munsell Book of Color,” J. Opt. Soc. Am. 30, 609 (1940). (7) K. L. Kelly, K. S. Gibson, and Dorothy Nickerson, ‘“‘Tristimulus specification of the Munsell Book of Color from spectrophotometric measurements,” J. Research Nat. Bur. Stand. (in press) and J. Opt. Soc. Am. 33, 355 (1943). (8) A. C. Hardy, Handbook of Colorimetry (Technology Press, 1936). (9) Dorothy Nickerson and Walter C. Granville, ‘‘Hue sensibility to dominant wave-length change and the relation between saturation and colorimetric purity,”’ J. Opt. Soc. Am. 30, 159 (1940). (10) S. M. Newhall, ‘Preliminary report of the O.S.A. subcommittee on the spacing of the Munsell colors,” J. Opt. Soc. Am. 30, 617 (1940). (11) S. M. Newhall, Dorothy Nickerson, and Deane B. Judd, ‘Final report of the O.S.A. subcommittee on the spacing of the Munsell colors,’ J. Opt. Soc. Am. 33, 385 (1943).

JOURNAL OF THE OPTICAL SOCIETY OF AMERICA

Final Report of the O.S.A. Subcommittee on the Spacing of the Munsell Colors

, Bausch & Lomb Optical Company, Rochester, New York,, United States Department of Agriculture, Washington, D. C., , National Bureau of Standards, Washington, D. C.

This report presents the characteristics of a modified and enlarged Munsell solid which has been evolved from the 1940 visual estimates of the Munsell Book of Color samples. All three dimensions have been carefully reviewed and extensively revised. The newly defined loci of constant hue have been extended closer to the extremes of value while the loci of constant chroma have been extrapolated to the pigment maximum. The dimension of value has been redefined without substantial departure from the Munsell-Sloan-Godlove scale. By the above changes a solid is achieved which approaches more closely to A. H. Munsell’s dual ideal of psychological equispacing and precise applicability. The new solid is defined in terms of the I.C.I. standard coordinate system and Illuminant C.

TABLE OF CONTENTS Introduction 386 Recommendations 386 Conversion Charts, Munsell hue and I.C.I. chromaticity 387 Conversion Table, Munsell hue and I.C.I. chromaticity  397 Conversion Table, Munsell value vs. I.C.1. luminous reflectance 406 Conversion Table, Munsell samples in terms of the recommended Munsell notation 408 Revision Procedures 407 Chroma adjustments 407 Hue adjustments 414 Value adjustments 416 Summary 417

INTRODUCTION

HE original purpose of the subcommittee was to reduce the psychological irregu-