ASTM E1360-05(2015)
(Practice)Standard Practice for Specifying Color by Using the Optical Society of America Uniform Color Scales System
Standard Practice for Specifying Color by Using the Optical Society of America Uniform Color Scales System
SIGNIFICANCE AND USE
5.1 Notational systems that specify and identify colors have proved to be very useful. This practice describes how to assign an OSA-UCS notation to a color specimen. This notation gives its position within the color space determined by the Optical Society of America Committee on Uniform Color Scales to represent the closest possible approximation to a color space in which equal distances equate to equal visually perceived differences. The cuboctahedral sampling fills the color space with a more closely spaced set of samples than would a cubic lattice or samples placed on polar coordinates.
SCOPE
1.1 This practice provides a means for specifying the colors of objects in terms of the Optical Society of America Uniform Color Scales. Both computational and visual methods are included. The practice is limited to opaque objects, such as painted surfaces, viewed in daylight by an observer having normal color vision.
1.2 This practice does not cover the preparation of specimens. If the preparation of specimens is required in conjunction with this practice, a mutually agreed upon procedure shall be established.
General Information
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Designation: E1360 − 05 (Reapproved 2015)
Standard Practice for
Specifying Color by Using the Optical Society of America
Uniform Color Scales System
This standard is issued under the fixed designation E1360; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
TheOpticalSocietyofAmericaUniformColorScales(OSA-UCS)weredevelopedbyacommittee
oftheOpticalSocietyofAmericaintheyearsbetween1947and1974inanefforttoprovideasystem
andasetofsamplesthatrepresenttheclosestpossibleapproximationtoequalvisualspacing (1). The
system is defined by a set of equations derived from the results of visual scaling experiments and
related to the 1964 CIE system. The OSA sample set consisted of 558 atlas samples that fell at the
lattice points of a rhombohedral close-packed arrangement within the color space defined by the
equations. The unit in this spacing is a cuboctahedron, each color being surrounded by twelve
equidistant nearest neighbors. See Fig. 1 and Fig. 2. Fig. 3 shows a OSA-UCS lightness plane plotted
on the CIE 1964 chromaticity diagram. The OSA-UCS system is described in Appendix X1.
The system is independent of the OSA-UCS atlas samples, and other groups of samples could be
chosenwithinthedefinedcolorspace;however,forthevisualdeterminationofcolorsdescribedinthis
standard, the OSA set of samples is used.
1. Scope D1729Practice for Visual Appraisal of Colors and Color
Differences of Diffusely-Illuminated Opaque Materials
1.1 This practice provides a means for specifying the colors
E284Terminology of Appearance
of objects in terms of the Optical Society ofAmerica Uniform
E308PracticeforComputingtheColorsofObjectsbyUsing
Color Scales. Both computational and visual methods are
the CIE System
included. The practice is limited to opaque objects, such as
E1164PracticeforObtainingSpectrometricDataforObject-
painted surfaces, viewed in daylight by an observer having
Color Evaluation
normal color vision.
1.2 This practice does not cover the preparation of speci-
3. Terminology
mens. If the preparation of specimens is required in conjunc-
3.1 Definitions of Terms Specific to This Standard:
tion with this practice, a mutually agreed upon procedure shall
be established.
3.1.1 chromaticness, n—an attribute of a visual sensation
combining hue and chroma; the visual correlate of the colori-
2. Referenced Documents
metric quantity chomaticity.
2.1 ASTM Standards:
3.1.2 hue, n—the attribute of color perception by means of
D1535PracticeforSpecifyingColorbytheMunsellSystem
which an object is judged to be red, yellow, green, blue, or
intermediate between some adjacent pair of these. In the
OSA-UCS system each hue is denoted by its angle within a
This practice is under the jurisdiction ofASTM Committee E12 on Color and
360° circle beginning in the yellow direction on the right hand
AppearanceandisthedirectresponsibilityofSubcommitteeE12.07onColorOrder
sideofthehuecircleandproceedingcounterclockwisethrough
Systems.
the greens, blues, and reds to return to the yellow hue, 360, on
Current edition approved May 1, 2015. Published May 2015. Originally
approved in 1990. Last previous edition approved in 2010 as E1360–05 (2010). the+j axis.
DOI: 10.1520/E1360-05R15.
2 3.1.3 OSA-UCS color system, n—Optical Society of
The boldface numbers in parentheses refer to a list of references at the end of
this practice.
America Uniform Color Scales color order system based on
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
equality of visual spacing, which uses the lightness scale 6L
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
and the opponent-color scales 6j(yellowness-blueness) and 6
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. g(greenness-redness).Acolor in the OSA-UCS system may be
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1360 − 05 (2015)
NOTE 1—Cuboctahedron showing location of L, j, and g axes through
its center and the locations and L, j, g coordinates of the center point and
its12nearestneighbors.ThelatticeoftheOSA-UCSsystemisderivedby
extending this unit in all directions to the extremes of color space. In this
NOTE 1—CIE 1964 (x , y )-chromaticity diagram showing chroma-
drawing horizontal nearest-neighbor planes are emphasized with heavy 10 10
ticitypoints(j,g)ofcolorsofOSAColorSystemforlightnesslevelL=0.
lines.FromBillmeyer,F.W.,Jr.,“SurveyofColorOrderSystems,”Color
The chromaticity point N is that of the nominal gray (D ) in the system.
Research and Application, Vol 12, (2). Copyright © 1987, John Wiley & 65
From Wyszecki, G., and Stiles, W. S., Color Science, 2nd ed., (3).
Sons.
Copyright 1982, John Wiley & Sons.
FIG. 1 Cuboctahedron Showing Axes and Horizontal Planes
FIG. 3 OSA L = O Plane on the CIE 1964 Chromaticity Diagram
which consisted of 558 samples displayed in a face-centered
lattice in three-dimensional space such that each interior
samplehas12nearestneighborsatequalintervalsfromit.This
configuration is sometimes referred to as a cuboctahedral or
rhombohedral lattice.
3.2 Definitions:
3.2.1 The definitions in Practice D1535 and Terminology
E284 are applicable to this practice.
4. Summary of Practice
4.1 Computation Method—CIE 1964 tristimulus values for
standard illuminant D and the 1964 supplementary (10°)
NOTE 1—Cuboctahedron of Fig. 1 showing a typical vertical plane ()
standard observer are obtained from spectrophotometric or
and a typical oblique plane (.) containing nearest-neighbor colors.
colorimetric measurements. See Practice E308 and Practice
From Billmeyer, F. W., Jr., “Survey of Color Order Systems,” Color
E1164. Transformation equations (5) from CIE 1964 tristimu-
Research and Application, Vol 12, (2). Copyright 1987, John Wiley &
lus values to OSA-UCS notations are given in Section 7, and
Sons.
the OSA-UCS notations and CIE specifications of the OSA
FIG. 2 Cuboctahedron Showing Vertical and Oblique Planes
atlas samples are given in Table 1.
4.2 Visual Method—Observers must have normal color
describedbyitsL,j,gnotationorbyitslightness,L;hueangle,
vision. Specimens should be viewed on an essentially nonse-
h , and chroma, c , designation.
OSA OSA lectivegraybackgroundof30%luminousreflectance,equiva-
lent to the OSA-UCS notationL=0,j=0,g=0, abbreviated
NOTE 1—The conventional terms yellowness, greenness, blueness, and
redness are used throughout this practice for convenience. However, this as (0,0,0), and illuminated with natural or artificial daylight.
does not imply that the j and g axes indicate the locations of the
OSA-UCS atlas samples are used as references in judging
corresponding unitary hues: The+j axis closely approximates the direc-
test-specimen color.
tion toward unitary yellow; but the+g axis divides the green and blue
regions, the−j axis divides the blue and purple regions, and the−g axis
5. Significance and Use
locates pinks and magentas. It is probably best to think of j and g as
abstract symbols unassociated with color names (4).
5.1 Notationalsystemsthatspecifyandidentifycolorshave
3.1.4 OSA-UCS samples, n—the Optical Society of Ameri- provedtobeveryuseful.Thispracticedescribeshowtoassign
ca’s physical exemplification of the OSA-UCS color system, anOSA-UCSnotationtoacolorspecimen.Thisnotationgives
E1360 − 05 (2015)
TABLE 1 CIE Specification for OSA-UCS Notations
OSA Lattice Coordinates CIE Specifications OSA Lattice Coordinates CIE Specifications
L jg Y x y L jg Y x y
10 10 10 10 10 10
A: Full-Step Colors A: Full-Step Colors
−7 −3 −1 3.22 0.2588 0.2169 0 −6 10.29 0.4236 0.2940
−3 1 3.24 0.2152 0.2251 0 −4 10.83 0.3875 0.3053
0 −2 11.25 0.3511 0.3176
−1 −1 3.54 0.3113 0.2841 0 0 11.53 0.3139 0.3309
−1 1 3.59 0.2569 0.3002 0 2 11.61 0.2756 0.3455
0 4 11.45 0.2357 0.3617
1 −1 3.79 0.3783 0.3571
1 1 3.92 0.3147 0.3858 2 −8 9.49 0.5132 0.3159
2 −6 10.27 0.4751 0.3304
−6 −4 −2 4.85 0.2656 0.2044 2 −4 11.00 0.4363 0.3461
−4 0 4.89 0.2304 0.2101 2 −2 11.62 0.3968 0.3631
−4 2 4.88 0.1960 0.2164 2 0 12.04 0.3564 0.3816
2 2 12.18 0.3145 0.4023
−2 −4 5.05 0.3508 0.2471 2 4 11.97 0.2699 0.4262
−2 −2 5.22 0.3090 0.2565
−2 0 5.32 0.2665 0.2670 4 −8 9.06 0.5677 0.3432
−2 2 5.32 0.2239 0.2783 4 −6 9.97 0.5289 0.3627
4 −4 10.89 0.4883 0.3837
0 −6 4.85 0.4574 0.2841 4 −2 11.70 0.4466 0.4063
0 −4 5.24 0.4103 0.2981 4 0 12.29 0.4038 0.4310
0 −2 5.56 0.3626 0.3136 4 2 12.52 0.3592 0.4590
0 0 5.75 0.3139 0.3309 4 4 12.29 0.3110 0.4927
0 2 5.78 0.2632 0.3505
−3 −5 −1 13.44 0.2529 0.2238
2 −6 5.00 0.5240 0.3260 −5 1 13.48 0.2276 0.2287
2 −4 5.24 0.4774 0.3475 −5 3 13.45 0.2025 0.2339
2 −2 5.73 0.4249 0.3710
2 0 6.06 0.3709 0.3974 −3 −5 13.71 0.3372 0.2488
2 2 6.13 0.3139 0.4283 −3 −3 14.01 0.3088 0.2552
−3 −1 14.21 0.2802 0.2621
−5 −5 −1 6.97 0.2402 0.1997 −3 1 14.30 0.2515 0.2694
−5 1 6.99 0.2114 0.2044 −3 3 14.27 0.2224 0.2772
−5 3 6.96 0.1829 0.2095 −3 5 14.11 0.1930 0.2855
−3 −3 7.35 0.3069 0.2380 −1 −7 13.63 0.4063 0.2760
−3 −1 7.48 0.2723 0.2454 −1 −5 14.18 0.3754 0.2845
−3 1 7.52 0.2375 0.2533 −1 −3 14.64 0.3442 0.2937
−3 3 7.48 0.2027 0.2619 −1 −1 14.97 0.3126 0.3035
−1 1 15.14 0.2805 0.3140
−1 −5 7.42 0.3907 0.2740 −1 3 15.12 0.2476 0.3254
−1 −3 7.76 0.3516 0.2848 −1 5 14.89 0.2136 0.3377
−1 −1 8.00 0.3122 0.2965
−1 1 8.10 0.2720 0.3093 1 −9 12.89 0.4840 0.2981
−1 3 8.05 0.2305 0.3233 1 −7 13.71 0.4510 0.3089
1 −5 14.47 0.4176 0.3206
1 −7 6.95 0.4886 0.3026 1 −3 15.13 0.3839 0.3329
1 −5 7.53 0.4463 0.3171 1 −1 15.62 0.3496 0.3465
1 −3 8.04 0.4034 0.3329 1 1 15.90 0.3146 0.3609
1 −1 8.43 0.3596 0.3503 1 3 15.90 0.2782 0.3771
1 1 8.62 0.3147 0.3695 1 5 15.57 0.2397 0.3950
1 3 8.56 0.2670 0.3916
3 −9 12.53 0.5328 0.3256
3 −7 6.67 0.5505 0.3363 3 −7 13.53 0.4984 0.3399
3 −5 7.39 0.5063 0.3568 3 −5 14.50 0.4631 0.3553
3 −3 8.08 0.4604 0.3791 3 −3 15.37 0.4272 0.3717
3 −1 8.65 0.4132 0.4035 3 −1 16.05 0.3906 0.3893
3 1 8.96 0.3646 0.4307 3 1 16.46 0.3581 0.4087
3 3 8.89 0.3127 0.4631 3 3 16.49 0.3139 0.4305
3 5 16.03 0.2716 0.4561
−4 −4 −2 10.12 0.2758 0.2303
−4 0 10.20 0.2465 0.2362 5 −7 13.07 0.5465 0.3666
−4 2 10.21 0.2172 0.2425 5 −5 14.21 0.5104 0.3863
−4 4 10.13 0.1881 0.2492 5 −3 15.28 0.4732 0.4073
5 −1 16.17 0.4349 0.4299
−2 −4 10.45 0.3435 0.2642 5 1 16.72 0.3956 0.4548
−2 −2 10.72 0.3104 0.2726 5 3 16.78 0.3543 0.4837
−2 0 10.88 0.2770 0.2818 5 5 16.20 0.3092 0.5189
−2 2 10.91 0.2430 0.2914
−2 4 10.80 0.2084 0.3022
A: Full-Step Colors A: Full-Step Colors
−2 −6 0 17.31 0.2354 0.2183 1 −9 22.22 0.4541 0.3038
−6 2 17.31 0.2133 0.2225 1 −7 23.26 0.4268 0.3129
1 −5 24.20 0.3993 0.3226
E1360 − 05 (2015)
TABLE 1 Continued
OSA Lattice Coordinates CIE Specifications OSA Lattice Coordinates CIE Specifications
L jg Y x y L jg Y x y
10 10 10 10 10 10
−4 −2 18.10 0.2824 0.2474 1 −3 25.00 0.3714 0.3330
−4 0 18.23 0.2574 0.2531 1 −1 25.60 0.3432 0.3439
−4 2 18.26 0.2323 0.2591 1 1 25.96 0.3145 0.3555
−4 4 18.18 0.2071 0.2655 1 3 26.02 0.2849 0.3682
1 5 25.75 0.2541 0.3820
−2 −6 18.09 0.3658 0.2683
−2 −4 18.58 0.3386 0.2754 3 −9 21.97 0.4933 0.3291
−2 −2 18.96 0.3112 0.2829 3 −7 23.24 0.4646 0.3408
−2 0 19.19 0.2836 0.2910 3 −5 24.42 0.4357 0.3529
−2 2 19.27 0.2555 0.2995 3 −3 25.46 0.4063 0.3659
−2 4 19.16 0.2268 0.3086 3 −1 26.26 0.3764 0.3797
−2 6 18.87 0.1977 0.3182 3 1 26.77 0.3459 0.3946
3 3 26.89 0.3144 0.4109
0 −10 16.86 0.4609 0.2831 3 5 26.54 0.2812 0.4292
0 −8 17.71 0.4320 0.2914
0 −6 18.50 0.4029 0.3004 5 −9 21.43 0.5332 0.3520
0 −4 19.19 0.3736 0.3099 5 −7 22.89 0.5039 0.3664
0 −2 19.73 0.3440 0.3200 5 −5 24.31 0.4738 0.3815
0 0 20.10 0.3139 0.3309 5 −3 25.58 0.4432 0.3975
0 2 20.24 0.2831 0.3426 5 −1 26.60 0.4119 0.4146
0 4 20.12 0.2512 0.3553 5 1 27.26 0.3801 0.4330
0 6 19.71 0.2180 0.3692 5 3 27.45 0.3470 0.4535
5 5 27.01 0.3119 0.4773
2 −10 16.59 0.5043 0.3094
2 −8 17.65 0.4739 0.3203 7 −9 20.62 0.5724 0.3707
2 −6 18.66 0.4430 0.3320 7 −7 22.22 0.5431 0.3883
2 −4 19.57 0.4118 0.3443 7 −5 23.82 0.5127 0.4067
2 −2 20.32 0.3801 0.3577 7 −3 25.31 0.4814 0.4261
2 0 20.84 0.3479 0.3719 7 −1 26.55 0.4493 0.4468
2 2 21.07 0.3147 0.3874 7 1 27.38 0.4165 0.4694
2 4 20.93 0.2800 0.4046 7 3 27.63 0.3823 0.4948
2 6 20.35 0.2430 0.4243 7 5 27.09 0.3460 0.5249
4 −10 16.06 0.5486 0.3328 0 −6 0 26.50 0.2457 0.2349
4 −8 17.28 0.5175 0.3468 −6 2 26.52 0.2260 0.2391
4 −6 18.50 0.4853 0.3618
4 −4 19.64 0.4525 0.3775 −4 −2 27.49 0.2872 0.2598
4 −2 20.61 0.4192 0.3942 −4 0 27.68 0.2655 0.2652
4 0 21.32 0.3851 0.4124 −4 2 27.75 0.2437 0.2708
4 2 22.65 0.3500 0.4324 −4 4 27.68 0.2217 0.2767
4 4 21.49 0.3130 0.4551
−2 −4 28.12 0.3350 0.2835
6 −10 15.33 0.5915 0.3515 −2 −2 28.58 0.3118 0.2903
6 −8 18.65 0.5608 0.3691 −2 0 28.88 0.2883 0.2974
6 −6 18.02 0.5283 0.3877 −2 2 29.00 0.2644 0.3049
6 −4 19.36 0.4948 0.4072 −2 4 28.93 0.2401 0.3128
6 −2 20.55 0.4603 0.4282
6 0 21.45 0.4250 0.4508 0 −8 27.22 0.4130 0.2972
6 2 21.89 0.3885 0.4758 0 −6 28.14 0.3886 0.3050
6 4 21.91 0.3498 0.5046 0 −4 28.93 0.3640 0.3131
0 −2 29.57 0.3391 0.3218
−1 −5 −1 22.61 0.2618 0.2405 0 0 30.00 0.3138 0.3310
−5 1 22.69 0.2397 0.2454 0 2 30.20 0.2882 0.3406
−5 3 22.66 0.2176 0.2504 0 4 30.13 0.2617 0.3511
0 6 29.77 0.2345 0.3622
−3 −3 23.36 0.3099 0.2670
−3 −1 23.67 0.2856 0.2734 2 −8 27.35 0.4469 0.3230
−3 1 23.81 0.2612 0.2801 2 −6 28.50 0.4212 0.3327
−3 3 23.81 0.2364 0.2871 2 −4 29.52 0.3951 0.3429
−3 5 23.64 0.2113 0.2945 2 −2 30.36 0.3688 0.3537
2 0 30.95 0.3421 0.3652
−1 −7 22.97 0.3911 0.2841 2 2 31.25 0.3147 0.3775
−1 −5 23.68 0.3652 0.2917 2 4 31.19 0.2863 0.3909
−1 −3 24.27 0.3392 0.2996 2 6 30.73 0.2567 0.4056
−1 −1 24.70 0.3129 0.3081
−1 1 24.94 0.2861 0.3171 4 −8 27.16 0.4824 0.3475
−1 3 24.96 0.2588 0.3266
−1 5 24.74 0.2308 0.3369
A: Full-Step Colors A: Full-Step Colors
4 −6 28.55 0.4555 0.3594 9 −7 31.66 0.5387 0.4045
4 −4 29.81 0.4283 0.3719 9 −5 33.55 0.5126 0.4214
4 −2 30.87 0.4007 0.3852 9 −3 35.29 0.4858 0.4389
4 0 31.64 0.3726 0.3993 9 −1 36.76 0.4585 0.4578
4 2 32.05 0.3438 0.4146 9 1 37.79 0.4305 0.4780
E1360 − 05 (2015)
TABLE 1 Continued
OSA Lattice Coordinates CIE Specifications OSA Lattice Coordinates CIE Specifications
L jg Y x y L jg Y x y
10 10 10 10 10 10
4 4 32.01 0.3139 0.4315 9 3 38.24 0.4017 0.5003
4 6 31.42 0.2822 0.4506
2 −4 0 39.65 0.2716 0.2739
6 −8 26.63 0.5186 0.3697 −4 2 39.76 0.2523 0.2792
6 −6 28.24 0.4910 0.3841 −4 4 39.71 0.2329 0.2847
6 −4 29.74 0.4629 0.3992
6 −2 31.02 0.4343 0.4152 −2 −4 40.
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1360 − 05 (Reapproved 2010) E1360 − 05 (Reapproved 2015)
Standard Practice for
Specifying Color by Using the Optical Society of America
Uniform Color Scales System
This standard is issued under the fixed designation E1360; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
The Optical Society of America Uniform Color Scales (OSA-UCS) were developed by a committee
of the Optical Society of America in the years between 1947 and 1974 in an effort to provide a system
and a set of samples that represent the closest possible approximation to equal visual spacing (1). The
system is defined by a set of equations derived from the results of visual scaling experiments and
related to the 1964 CIE system. The OSA sample set consisted of 558 atlas samples that fell at the
lattice points of a rhombohedral close-packed arrangement within the color space defined by the
equations. The unit in this spacing is a cuboctahedron, each color being surrounded by twelve
equidistant nearest neighbors. See Fig. 1 and Fig. 2. Fig. 3 shows a OSA-UCS lightness plane plotted
on the CIE 1964 chromaticity diagram. The OSA-UCS system is described in Appendix X1.
The system is independent of the OSA-UCS atlas samples, and other groups of samples could be
chosen within the defined color space; however, for the visual determination of colors described in this
standard, the OSA set of samples is used.
1. Scope
1.1 This practice provides a means for specifying the colors of objects in terms of the Optical Society of America Uniform Color
Scales. Both computational and visual methods are included. The practice is limited to opaque objects, such as painted surfaces,
viewed in daylight by an observer having normal color vision.
1.2 This practice does not cover the preparation of specimens. If the preparation of specimens is required in conjunction with
this practice, a mutually agreed upon procedure shall be established.
2. Referenced Documents
2.1 ASTM Standards:
D1535 Practice for Specifying Color by the Munsell System
D1729 Practice for Visual Appraisal of Colors and Color Differences of Diffusely-Illuminated Opaque Materials
E284 Terminology of Appearance
E308 Practice for Computing the Colors of Objects by Using the CIE System
E1164 Practice for Obtaining Spectrometric Data for Object-Color Evaluation
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 chromaticness, n—an attribute of a visual sensation combining hue and chroma; the visual correlate of the colorimetric
quantity chomaticity.
This practice is under the jurisdiction of ASTM Committee E12 on Color and Appearance and is the direct responsibility of Subcommittee E12.07 on Color Order
Systems.
Current edition approved July 1, 2010May 1, 2015. Published July 2010May 2015. Originally approved in 1990. Last previous edition approved in 20052010 as
E1360 – 05.E1360 – 05 (2010). DOI: 10.1520/E1360-05R10.10.1520/E1360-05R15.
The boldface numbers in parentheses refer to a list of references at the end of this practice.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1360 − 05 (2015)
NOTE 1—Cuboctahedron showing location of L, j, and g axes through its center and the locations and L, j, g coordinates of the center point and its
12 nearest neighbors. The lattice of the OSA-UCS system is derived by extending this unit in all directions to the extremes of color space. In this drawing
horizontal nearest-neighbor planes are emphasized with heavy lines. From Billmeyer, F. W., Jr., “Survey of Color Order Systems,” Color Research and
Application, Vol 12, (2). Copyright © 1987, John Wiley & Sons.
FIG. 1 Cuboctahedron Showing Axes and Horizontal Planes
NOTE 1—Cuboctahedron of Fig. 1 showing a typical vertical plane () and a typical oblique plane (.) containing nearest-neighbor colors. From
Billmeyer, F. W., Jr., “Survey of Color Order Systems,” Color Research and Application, Vol 12, (2). Copyright 1987, John Wiley & Sons.
FIG. 2 Cuboctahedron Showing Vertical and Oblique Planes
3.1.2 hue, n—the attribute of color perception by means of which an object is judged to be red, yellow, green, blue, or
intermediate between some adjacent pair of these. In the OSA-UCS system each hue is denoted by its angle within a 360° circle
beginning in the yellow direction on the right hand side of the hue circle and proceeding counterclockwise through the greens,
blues, and reds to return to the yellow hue, 360, on the + j axis.
3.1.3 OSA-UCS color system, n—Optical Society of America Uniform Color Scales color order system based on equality of
visual spacing, which uses the lightness scale 6L and the opponent-color scales 6j(yellowness-blueness) and 6 g(greenness-
redness). A color in the OSA-UCS system may be described by its L, j, g notation or by its lightness, L; hue angle, h , and
OSA
chroma, c , designation.
OSA
NOTE 1—The conventional terms yellowness, greenness, blueness, and redness are used throughout this practice for convenience. However, this does
not imply that the j and g axes indicate the locations of the corresponding unitary hues: The + j axis closely approximates the direction toward unitary
yellow; but the + g axis divides the green and blue regions, the − j axis divides the blue and purple regions, and the − g axis locates pinks and magentas.
It is probably best to think of j and g as abstract symbols unassociated with color names (4).
3.1.4 OSA-UCS samples, n—the Optical Society of America’sAmerica’s physical exemplification of the OSA-UCS color
system, which consisted of 558 samples displayed in a face-centered lattice in three-dimensional space such that each interior
sample has 12 nearest neighbors at equal intervals from it. This configuration is sometimes referred to as a cuboctahedral or
rhombohedral lattice.
3.2 Definitions:
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NOTE 1—CIE 1964 (x , y )-chromaticity diagram showing chromaticity points (j, g) of colors of OSA Color System for lightness level L = 0. The
10 10
chromaticity point N is that of the nominal gray (D ) in the system. From Wyszecki, G., and Stiles, W. S., Color Science, 2nd ed., (3). Copyright 1982,
John Wiley & Sons.
FIG. 3 OSA L = O Plane on the CIE 1964 Chromaticity Diagram
3.2.1 The definitions in Practice D1535 and Terminology E284 are applicable to this practice.
4. Summary of Practice
4.1 Computation Method—CIE 1964 tristimulus values for standard illuminant D and the 1964 supplementary (10°) standard
observer are obtained from spectrophotometric or colorimetric measurements. See Practice E308 and Practice E1164.
Transformation equations (5) from CIE 1964 tristimulus values to OSA-UCS notations are given in Section 7, and the OSA-UCS
notations and CIE specifications of the OSA atlas samples are given in Table 1.
4.2 Visual Method—Observers must have normal color vision. Specimens should be viewed on an essentially nonselective gray
background of 30 % luminous reflectance, equivalent to the OSA-UCS notation L = 0, j = 0, g = 0, abbreviated as (0,0,0), and
illuminated with natural or artificial daylight. OSA-UCS atlas samples are used as references in judging test-specimen color.
5. Significance and Use
5.1 Notational systems that specify and identify colors have proved to be very useful. This practice describes how to assign an
OSA-UCS notation to a color specimen. This notation gives its position within the color space determined by the Optical Society
of America Committee on Uniform Color Scales to represent the closest possible approximation to a color space in which equal
distances equate to equal visually perceived differences. The cuboctahedral sampling fills the color space with a more closely
spaced set of samples than would a cubic lattice or samples placed on polar coordinates.
6. Apparatus (Visual Method)
6.1 Optical Society of America Uniform Color Scales, set of 558 samples.
6.2 Daylight Illuminating Equipment, as described in Practice D1729 or equivalent. A source simulating CIE standard
illuminant D is preferred.
7. OSA-UCS Notations from CIE Coordinates
7.1 OSA-UCS Color Space—The three coordinates of the OSA Committee’s color space are (L, j, g) standing for lightness,
yellowness-blueness, and greeness-redness, respectively (see Note 1.) The initial j (from the French word jaune, for yellow) is used
to avoid confusion with the CIE chromaticity coordinate y. The quantity L was derived from the Committee’s original lightness
scale factor, Λ . Λ.
L 5 Λ2 14.4 /=2 (1)
~ !
These sets are no longer available commercially.
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TABLE 1 CIE Specification for OSA-UCS Notations
OSA Lattice Coordinates CIE Specifications OSA Lattice Coordinates CIE Specifications
L j g Y x y L j g Y x y
10 10 10 10 10 10
A: Full-Step Colors A: Full-Step Colors
−7 −3 −1 3.22 0.2588 0.2169 0 −6 10.29 0.4236 0.2940
−3 1 3.24 0.2152 0.2251 0 −4 10.83 0.3875 0.3053
0 −2 11.25 0.3511 0.3176
−1 −1 3.54 0.3113 0.2841 0 0 11.53 0.3139 0.3309
−1 1 3.59 0.2569 0.3002 0 2 11.61 0.2756 0.3455
0 4 11.45 0.2357 0.3617
1 −1 3.79 0.3783 0.3571
1 1 3.92 0.3147 0.3858 2 −8 9.49 0.5132 0.3159
2 −6 10.27 0.4751 0.3304
−6 −4 −2 4.85 0.2656 0.2044 2 −4 11.00 0.4363 0.3461
−4 0 4.89 0.2304 0.2101 2 −2 11.62 0.3968 0.3631
−4 2 4.88 0.1960 0.2164 2 0 12.04 0.3564 0.3816
2 2 12.18 0.3145 0.4023
−2 −4 5.05 0.3508 0.2471 2 4 11.97 0.2699 0.4262
−2 −2 5.22 0.3090 0.2565
−2 0 5.32 0.2665 0.2670 4 −8 9.06 0.5677 0.3432
−2 2 5.32 0.2239 0.2783 4 −6 9.97 0.5289 0.3627
4 −4 10.89 0.4883 0.3837
0 −6 4.85 0.4574 0.2841 4 −2 11.70 0.4466 0.4063
0 −4 5.24 0.4103 0.2981 4 0 12.29 0.4038 0.4310
0 −2 5.56 0.3626 0.3136 4 2 12.52 0.3592 0.4590
0 0 5.75 0.3139 0.3309 4 4 12.29 0.3110 0.4927
0 2 5.78 0.2632 0.3505
−3 −5 −1 13.44 0.2529 0.2238
2 −6 5.00 0.5240 0.3260 −5 1 13.48 0.2276 0.2287
2 −4 5.24 0.4774 0.3475 −5 3 13.45 0.2025 0.2339
2 −2 5.73 0.4249 0.3710
2 0 6.06 0.3709 0.3974 −3 −5 13.71 0.3372 0.2488
2 2 6.13 0.3139 0.4283 −3 −3 14.01 0.3088 0.2552
−3 −1 14.21 0.2802 0.2621
−5 −5 −1 6.97 0.2402 0.1997 −3 1 14.30 0.2515 0.2694
−5 1 6.99 0.2114 0.2044 −3 3 14.27 0.2224 0.2772
−5 3 6.96 0.1829 0.2095 −3 5 14.11 0.1930 0.2855
−3 −3 7.35 0.3069 0.2380 −1 −7 13.63 0.4063 0.2760
−3 −1 7.48 0.2723 0.2454 −1 −5 14.18 0.3754 0.2845
−3 1 7.52 0.2375 0.2533 −1 −3 14.64 0.3442 0.2937
−3 3 7.48 0.2027 0.2619 −1 −1 14.97 0.3126 0.3035
−1 1 15.14 0.2805 0.3140
−1 −5 7.42 0.3907 0.2740 −1 3 15.12 0.2476 0.3254
−1 −3 7.76 0.3516 0.2848 −1 5 14.89 0.2136 0.3377
−1 −1 8.00 0.3122 0.2965
−1 1 8.10 0.2720 0.3093 1 −9 12.89 0.4840 0.2981
−1 3 8.05 0.2305 0.3233 1 −7 13.71 0.4510 0.3089
1 −5 14.47 0.4176 0.3206
1 −7 6.95 0.4886 0.3026 1 −3 15.13 0.3839 0.3329
1 −5 7.53 0.4463 0.3171 1 −1 15.62 0.3496 0.3465
1 −3 8.04 0.4034 0.3329 1 1 15.90 0.3146 0.3609
1 −1 8.43 0.3596 0.3503 1 3 15.90 0.2782 0.3771
1 1 8.62 0.3147 0.3695 1 5 15.57 0.2397 0.3950
1 3 8.56 0.2670 0.3916
3 −9 12.53 0.5328 0.3256
3 −7 6.67 0.5505 0.3363 3 −7 13.53 0.4984 0.3399
3 −5 7.39 0.5063 0.3568 3 −5 14.50 0.4631 0.3553
3 −3 8.08 0.4604 0.3791 3 −3 15.37 0.4272 0.3717
3 −1 8.65 0.4132 0.4035 3 −1 16.05 0.3906 0.3893
3 1 8.96 0.3646 0.4307 3 1 16.46 0.3581 0.4087
3 3 8.89 0.3127 0.4631 3 3 16.49 0.3139 0.4305
3 5 16.03 0.2716 0.4561
−4 −4 −2 10.12 0.2758 0.2303
−4 0 10.20 0.2465 0.2362 5 −7 13.07 0.5465 0.3666
−4 2 10.21 0.2172 0.2425 5 −5 14.21 0.5104 0.3863
−4 4 10.13 0.1881 0.2492 5 −3 15.28 0.4732 0.4073
5 −1 16.17 0.4349 0.4299
−2 −4 10.45 0.3435 0.2642 5 1 16.72 0.3956 0.4548
−2 −2 10.72 0.3104 0.2726 5 3 16.78 0.3543 0.4837
−2 0 10.88 0.2770 0.2818 5 5 16.20 0.3092 0.5189
−2 2 10.91 0.2430 0.2914
−2 4 10.80 0.2084 0.3022
A: Full-Step Colors A: Full-Step Colors
−2 −6 0 17.31 0.2354 0.2183 1 −9 22.22 0.4541 0.3038
−6 2 17.31 0.2133 0.2225 1 −7 23.26 0.4268 0.3129
1 −5 24.20 0.3993 0.3226
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TABLE 1 Continued
OSA Lattice Coordinates CIE Specifications OSA Lattice Coordinates CIE Specifications
L j g Y x y L j g Y x y
10 10 10 10 10 10
−4 −2 18.10 0.2824 0.2474 1 −3 25.00 0.3714 0.3330
−4 0 18.23 0.2574 0.2531 1 −1 25.60 0.3432 0.3439
−4 2 18.26 0.2323 0.2591 1 1 25.96 0.3145 0.3555
−4 4 18.18 0.2071 0.2655 1 3 26.02 0.2849 0.3682
1 5 25.75 0.2541 0.3820
−2 −6 18.09 0.3658 0.2683
−2 −4 18.58 0.3386 0.2754 3 −9 21.97 0.4933 0.3291
−2 −2 18.96 0.3112 0.2829 3 −7 23.24 0.4646 0.3408
−2 0 19.19 0.2836 0.2910 3 −5 24.42 0.4357 0.3529
−2 2 19.27 0.2555 0.2995 3 −3 25.46 0.4063 0.3659
−2 4 19.16 0.2268 0.3086 3 −1 26.26 0.3764 0.3797
−2 6 18.87 0.1977 0.3182 3 1 26.77 0.3459 0.3946
3 3 26.89 0.3144 0.4109
0 −10 16.86 0.4609 0.2831 3 5 26.54 0.2812 0.4292
0 −8 17.71 0.4320 0.2914
0 −6 18.50 0.4029 0.3004 5 −9 21.43 0.5332 0.3520
0 −4 19.19 0.3736 0.3099 5 −7 22.89 0.5039 0.3664
0 −2 19.73 0.3440 0.3200 5 −5 24.31 0.4738 0.3815
0 0 20.10 0.3139 0.3309 5 −3 25.58 0.4432 0.3975
0 2 20.24 0.2831 0.3426 5 −1 26.60 0.4119 0.4146
0 4 20.12 0.2512 0.3553 5 1 27.26 0.3801 0.4330
0 6 19.71 0.2180 0.3692 5 3 27.45 0.3470 0.4535
5 5 27.01 0.3119 0.4773
2 −10 16.59 0.5043 0.3094
2 −8 17.65 0.4739 0.3203 7 −9 20.62 0.5724 0.3707
2 −6 18.66 0.4430 0.3320 7 −7 22.22 0.5431 0.3883
2 −4 19.57 0.4118 0.3443 7 −5 23.82 0.5127 0.4067
2 −2 20.32 0.3801 0.3577 7 −3 25.31 0.4814 0.4261
2 0 20.84 0.3479 0.3719 7 −1 26.55 0.4493 0.4468
2 2 21.07 0.3147 0.3874 7 1 27.38 0.4165 0.4694
2 4 20.93 0.2800 0.4046 7 3 27.63 0.3823 0.4948
2 6 20.35 0.2430 0.4243 7 5 27.09 0.3460 0.5249
4 −10 16.06 0.5486 0.3328 0 −6 0 26.50 0.2457 0.2349
4 −8 17.28 0.5175 0.3468 −6 2 26.52 0.2260 0.2391
4 −6 18.50 0.4853 0.3618
4 −4 19.64 0.4525 0.3775 −4 −2 27.49 0.2872 0.2598
4 −2 20.61 0.4192 0.3942 −4 0 27.68 0.2655 0.2652
4 0 21.32 0.3851 0.4124 −4 2 27.75 0.2437 0.2708
4 2 22.65 0.3500 0.4324 −4 4 27.68 0.2217 0.2767
4 4 21.49 0.3130 0.4551
−2 −4 28.12 0.3350 0.2835
6 −10 15.33 0.5915 0.351
...
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