Kasson S. Gibson and Geraldine Walker Haupt, "Standardization of the Luminous Transmission Scale Used in the Specification of Railroad Signal Glasses," J. Opt. Soc. Am. 29, 188-200 (1939)
This is the first of several papers dealing with the development and description of the signal glass specifications formulated by the Signal Section of the Association of American Railroads in 1935 and 1938. The present paper gives the spectral transmissions of the basic standards—red, yellow, green, blue, purple and lunar white glasses—on which the A. A. R. scale of luminous transmission is based, and defines that scale in fundamental, absolute units. Comparison is made with the scales defined in the 1908 and 1918 signal glass specifications.
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Spectral transmissions (percent) of the standard or medium roundels, designated as having a value of TRSA=100; 1908 specification.*
Wave-Length
Red
Yellow
Green
Blue
Purple
Lunar White
Fraunhofer Line
(Millimicron Equivalent)
A
(761)
60
0
0
0
0
0
a
(716)
65
38
0
0
42
62
B
(687)
70
50
0
0
42
49
C
(656)
72
43
0
0
0
17
D
(589)
0
41
4
3
0
15
E
(527)
0
12
27
4
0
25
b
(517)
0
9
40
6
0
38
F
(486)
0
3
45
24
2
65
G
(431)
0
0
25
40
43
74
H
(397)
0
0
0
46
42
0
Values taken from a copy of the original Specifications for Signal Roundels, Lenses and Glass Slides, Volume V, Railway Signal Association, 1908 Proceedings, kindly furnished the authors by Mr. R. H. C. Balliet, present Secretary, A. A. R. Signal Section.
Table II
Spectral transmissions (percent) of the medium roundels, having values of TRSA as indicated; 1918 specification as published.
Wave-Length (millimicrons)
RedTRSA=130
Yellow 120
Green 150
Blue 100
Purple 100
Lunar White 100
410
0
0
40
80
90
90
430
0
0
53
73
82
80
450
0
0
62
68
74
69
470
0
0
68
54
59
65
490
0
0
70
27
18
54
510
0
2
64
10
5
38
530
0
8
48
2
1
22
550
0
18
30
2
.5
23
570
0
29
16
1
.5
26
590
0
42
6
0
0
11
610
0
50
3
0
0
12
630
47
54
1
0
0
11.5
650
74
57
0
0
0
10.5
670
78
57
0
0
.2
23
690
75
55
0
1
12
51
710
74
52
0
2
52
79
Table III
Designations of roundels selected in 1930 as the basis of the A. R. A. scale of luminous transmission.
Identifying number of roundel
Color designation of roundel
Corning values of transmission on A. R. A. scale
5
Red
97
0
Yellow
100
4
Green
100
6
Blue
105
4
Purple
101.3
3
Lunar white
100
Table IV
Data obtained by one of the authors (K. S. G.) at Corning Glass Works on the glasses selected to replace the former A. R. A. standard roundels.
The record shows comments on but two of the six blue glasses. It is uncertain whether the other four should be designated “more saturated” or “match.”
Table V
Spectral transmissions of the A, B and C glasses (comprising 18 of the 36 glasses listed in Tables IV and VI.
Red
Yellow
Green
Blue
Purple
Lunar White
Wave-Length (millimicrons)
92 A
86 B
83 C
115 A
118 B
114 C
111 A
121 B
110 C
53 A
82 B
54 C
38 A
60 B
66 C
71 A
68 B
49 C
Hg
404.7
0.0000
0.0000
0.173
0.716
0.838
0.862
435.8
.0000
.0000
.340
.728
.724
.815
491.6
.0000
.0026
.500
.277
.162
.560
546.1
.0000
.1053
.211
.0130
.0031
.194
578.0
<.0001
.268
.0554
.0060
.0022
.177
380
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.028
0.028
0.028
0.477
0.468
0.472
0.783
0.783
0.783
0.795
0.795
0.795
90
.070
.069
.070
.616
.604
.610
.845
.841
.840
.845
.845
.846
400
.139
.138
.139
.695
.689
.693
.852
.845
.844
.862
.861
.862
10
.207
.205
.206
.738
.731
.737
.830
.824
.824
.854
.854
.855
20
.264
.262
.264
.749
.742
.749
.791
.786
.786
.834
.834
.834
30
.317
.315
.317
.742
.736
.742
.755
.750
.750
.822
.822
.823
40
.360
.358
.359
.726
.721
.726
.709
.705
.705
.810
.810
.812
450
.0000
.0000
.0000
.407
.406
.407
.699
.693
.698
.657
.653
.653
.799
.799
.801
60
.0001
.0001
.0001
.451
.451
.452
.655
.649
.653
.593
.589
.589
.780
.781
.783
70
.0003
.0003
.0003
.481
.481
.481
.569
.564
.567
.473
.471
.473
.738
.739
.741
80
.0008
.0008
.0008
.497
.497
.497
.440
.437
.439
.318
.318
.320
.664
.665
.667
90
.0022
.0021
.0021
.501
.501
.501
.302
.300
.301
.181
.181
.182
.569
.569
.570
500
.0056
.0054
.0055
.486
.486
.485
.201
.200
.200
.1010
.1015
.1023
.497
.497
.497
10
.0132
.0128
.0130
.450
.450
.450
.1120
.1115
.1112
.0443
.0447
.0449
.397
.397
.397
20
.0266
.0261
.0265
.395
.394
.395
.0551
.0550
.0546
.0161
.0163
.0163
.302
.302
.301
30
.0494
.0483
.0489
.330
.328
.329
.0222
.0222
.0220
.0048
.0049
.0049
.220
.220
.219
40
.0814
.0798
.0807
.255
.253
.255
.0131
.0132
.0131
.0027
.0028
.0028
.184
.185
.184
550
.1237
.1218
.1228
.185
.183
.185
.0152
.0152
.0150
.0042
.0043
.0043
.210
.211
.210
60
.174
.172
.173
.1289
.1268
.1289
.0210
.0210
.0208
.0091
.0092
.0092
.257
.257
.257
70
.0000
.226
.224
.225
.0844
.0824
.0844
.0146
.0147
.0145
.0067
.0069
.0069
.241
.241
.240
80
.0001
.0000
.280
.278
.280
.0525
.0509
.0526
.0045
.0046
.0045
.0016
.0017
.0017
.160
.160
.159
90
.0000
.0002
.0002
.327
.325
.326
.0309
.0296
.0309
.0011
.0011
.0011
.0003
.0003
.0003
.0964
.0962
.0954
600
.0001
.0005
.0004
.368
.366
.367
.0174
.0165
.0174
.0008
.0008
.0008
.0002
.0002
.0002
.0951
.0950
.0938
10
.0013
.0019
.0013
.402
.400
.401
.0099
.0093
.0099
.0008
.0008
.0008
.0003
.0003
.0003
.1059
.1058
.1047
20
.065
.022
.015
.428
.426
.428
.0055
.0051
.0055
.0006
.0006
.0006
.0004
.0004
.0004
.1090
.1090
.1082
30
.38
.23
.18
.446
.444
.446
.0030
.0027
.0030
.0004
.0004
.0004
.0003
.0003
.0003
.1036
.1035
.1025
40
.60
.65
.61
.459
.457
.458
.0017
.0015
.0017
.0003
.0003
.0003
.0002
.0002
.0002
.0936
.0935
.0923
650
.678
.798
.785
.469
.467
.468
.0009
.0008
.0009
.0002
.0002
.0002
.0003
.0003
.0003
.0980
.0980
.0970
60
.717
.833
.823
.475
.473
.474
.0005
.0004
.0005
.0004
.0004
.0004
.0008
.0008
.0008
.132
.132
.131
70
.738
.844
.834
.478
.476
.477
.0002
.0002
.0002
.0009
.0009
.0009
.005
.005
.005
.21
.21
.21
80
.754
.852
.841
.479
.477
.479
.0001
.0001
.0001
.0021
.0021
.0021
.034
.035
.036
.36
.36
.36
90
.764
.856
.846
.477
.475
.477
.0000
.0000
.0000
.0045
.0045
.0044
.16
.16
.16
.55
.55
.55
700
.769
.858
.848
.474
.472
.473
.008
.008
.008
.40
.40
.40
.71
.71
.71
10
.772
.859
.850
.468
.467
.468
.009
.009
.009
.65
.65
.65
.810
.810
.811
20
.770
.858
.850
.460
.459
.460
.0085
.0085
.0085
.798
.795
.795
.851
.852
.853
30
.768
857
.849
.450
.449
.450
.008
.008
.008
.860
.857
.857
.868
.868
.869
40
.764
.855
.848
.439
.438
.439
.0075
.0075
.0075
.885
.883
.883
.873
.873
.873
750
.758
.852
.845
.427
.426
.427
.007
.007
.007
.896
.893
.893
.876
.877
.877
60
.751
.849
.842
.413
.412
.412
.0000
.0000
.0000
.0065
.0065
.0065
.900
.896
.896
.876
.877
.877
Luminous Transmission, T2360 (C2=14,350)
0.07341
.07110
.06628
.2526
.2508
.2520
.1218
.1205
.1217
.02246
.02240
.02233
.01299
.01306
.01312
.1889
.1890
.1882
Table VI
Derivation of new A. R. A. transmissions (redefined as A. A. R. transmissions) for the 36 glasses listed in Table IV.
Designation
Relative Luminous Transmission (at 2360°K) as determined at National Bureau of Standards in 1932
A. R. A. Transmission
Color
Ref.
No.
Mean, by 3 Observers with Martens Photometer
Av. Dev. of each Observer from Mean
Computed from Spectral Transmission
Mean, Columns 3 and 5
Dev. from Mean, Col. 3 (or 5) minus Col. 6
As Labeled at Corning
By K. S. G. at Corning
New A. R. A. TransmissionT′ARA
Luminous TransmissionT2360
T2360 Equivalent toT′ARA=TAAR=100.0
Red
C
83
0.9383
0.0051
0.9323
0.9353
±.0030
95.2
97.5
96.2
0.06628
0.06890
B
86
1.0000
1.0000
1.0000
.0000
101.
102.6
102.9
.07110
.06910
B′
88
1.0303
.0021
1.0303
105.
104.6
106.0
C′
91
1.0022
.0213
1.0022
100.
103.1
103.1
A
92
1.0335
.0120
1.0325
1.0330
.0005
100.
106.4
106.3
.07341
.06906
A′
93
.9886
.0103
.9886
97.
102.0
101.7
Means
.0102
.9982
(f=102.89)
102.7
102.7
.0690
Yellow
C
114
1.0056
.0015
1.0047
1.0052
.0004
100.
101.3
101.8
.2520
.2475
A
115
1.0098
.0022
1.0073
1.0086
.0012
100.
101.7
102.2
.2526
.2472
A′
116
1.0051
.0018
1.0051
100.
102.5
101.8
B′
117
1.0038
.0017
1.0038
100.
102.1
101.7
B
118
1.0000
1.0000
1.0000
.0000
100.
101.1
101.3
.2508
.2476
C′
138
1.0011
.0011
1.0011
100.
101.5
101.4
Means
.0017
1.0040
(f=101.29)
101.7
101.7
.2474
Green
C
110
1.0134
.0021
1.0098
1.0116
.0018
102.
103.1
102.6
.1217
.1186
A
111
1.0158
.0019
1.0105
1.0132
.0026
102.
102.7
102.8
.1218
.1185
A′
112
1.0087
.0018
1.0087
102.
102.1
102.3
C′
113
1.0177
.0025
1.0177
102.
103.3
103.2
B′
120
.9952
.0014
.9952
100.
100.6
100.9
B
121
1.0000
1.0000
1.0000
.0000
100.
101.5
101.4
.1205
.1188
Means
.0019
1.0077
(f=101.42)
102.2
102.2
.1186
Blue
A′
52
1.0113
.0029
1.0113
100.
101.4
101.4
A
53
1.0024
.0020
1.0029
1.0026
.0002
100.
100.6
100.6
.02246
.02233
C
54
.9950
.0040
.9969
.9960
.0010
100.
99.4
99.9
.02233
.02235
C′
79
.9924
.0037
.9924
100.
99.7
99.5
B′
81
.9923
.0015
.9923
100.
99.2
99.5
B
82
1.0000
1.0000
1.0000
.0000
100.
100.7
100.3
.02240
.02233
Means
.0028
.9991
(f=100.29)
100.2
100.2
.02234
Purple
A
38
.9942
.0024
.9944
.9943
.0001
100.
101.0
100.7
.01299
.01290
A′
39
.9931
.0032
.9931
100.
101.0
100.5
B
60
1.0000
1.0000
1.0000
.0000
100.
101.0
101.2
.01306
.01291
C
66
1.0051
.0018
1.0046
1.0048
.0002
101.
101.2
101.7
.01312
.01290
C′
67
1.0004
.0025
1.0004
101.
101.5
101.3
B′
68
.9937
.0023
.9937
100.
100.3
100.6
Means
.0024
.9977
(f=101.23)
101.0
101.0
.01290
Lunar white
C′
40
1.0214
.0015
1.0214
101.
101.0
101.9
C
49
.9979
.0024
.9959
.9969
.0010
99.5
100.0
99.4
.1882
.1893
A′
67
.9977
.0022
.9977
100.
98.9
99.5
B
68
1.0000
1.0000
1.0000
.0000
100.
100.1
99.8
.1890
.1894
B′
69
.9946
.0006
.9946
100.
99.5
99.2
A
71
.9972
.0010
.9993
.9982
.0010
100.
99.9
99.6
.1889
.1897
Means
.0015
1.0015
(f=99.75)
99.9
99.9
.1895
1
2
3
4
5
6
7
8
9
10
11
12
Table VII
Relation between values of TAAR and of T2360, which defines the luminous transmission scale established in the 1935 and 1938 A. A. R. signal glass specifications.
Color designation of glass
A. A. R. transmission, TAAR
Equivalent luminous transmission, 1931 I. C. I. standard observer, illuminant 2360°K, T2360
The original derived value was 0.1895 (Table VI). This was at first cut back to 0.189 and was so published in Report 5 and in J. Opt. Soc. Am. 24, 57 (1934). Later work has, however, indicated that 0.190 is a more accurate conversion factor than 0.189.
Table VIII
Comparison of values of T2360 computed for values of TRSA=100.0 from the 1918 specification, with similar values for TAAR=100.0 computed from data on which the 1935 specification is based.
Color Designation
T2360
ΔT2360 (column 2 minus column 3)
Percent change inT2360 (column 4 divided by column 3, ×100)
TRSA=100.0 (1918)
TAAR=100.0 (1935)
Red
0.0662
0.0672
−0.0010
−1.5
Yellow
.268
.247
+ .021
+8.5
Green
.129
.119
+ .010
+8.4
Blue
.0203
.0221
− .0018
−8.1
Purple
.0134
.0124
+ .0010
+8.1
Lunar white
.199
.189
+ .010
+5.3
Tables (8)
Table I
Spectral transmissions (percent) of the standard or medium roundels, designated as having a value of TRSA=100; 1908 specification.*
Wave-Length
Red
Yellow
Green
Blue
Purple
Lunar White
Fraunhofer Line
(Millimicron Equivalent)
A
(761)
60
0
0
0
0
0
a
(716)
65
38
0
0
42
62
B
(687)
70
50
0
0
42
49
C
(656)
72
43
0
0
0
17
D
(589)
0
41
4
3
0
15
E
(527)
0
12
27
4
0
25
b
(517)
0
9
40
6
0
38
F
(486)
0
3
45
24
2
65
G
(431)
0
0
25
40
43
74
H
(397)
0
0
0
46
42
0
Values taken from a copy of the original Specifications for Signal Roundels, Lenses and Glass Slides, Volume V, Railway Signal Association, 1908 Proceedings, kindly furnished the authors by Mr. R. H. C. Balliet, present Secretary, A. A. R. Signal Section.
Table II
Spectral transmissions (percent) of the medium roundels, having values of TRSA as indicated; 1918 specification as published.
Wave-Length (millimicrons)
RedTRSA=130
Yellow 120
Green 150
Blue 100
Purple 100
Lunar White 100
410
0
0
40
80
90
90
430
0
0
53
73
82
80
450
0
0
62
68
74
69
470
0
0
68
54
59
65
490
0
0
70
27
18
54
510
0
2
64
10
5
38
530
0
8
48
2
1
22
550
0
18
30
2
.5
23
570
0
29
16
1
.5
26
590
0
42
6
0
0
11
610
0
50
3
0
0
12
630
47
54
1
0
0
11.5
650
74
57
0
0
0
10.5
670
78
57
0
0
.2
23
690
75
55
0
1
12
51
710
74
52
0
2
52
79
Table III
Designations of roundels selected in 1930 as the basis of the A. R. A. scale of luminous transmission.
Identifying number of roundel
Color designation of roundel
Corning values of transmission on A. R. A. scale
5
Red
97
0
Yellow
100
4
Green
100
6
Blue
105
4
Purple
101.3
3
Lunar white
100
Table IV
Data obtained by one of the authors (K. S. G.) at Corning Glass Works on the glasses selected to replace the former A. R. A. standard roundels.
The record shows comments on but two of the six blue glasses. It is uncertain whether the other four should be designated “more saturated” or “match.”
Table V
Spectral transmissions of the A, B and C glasses (comprising 18 of the 36 glasses listed in Tables IV and VI.
Red
Yellow
Green
Blue
Purple
Lunar White
Wave-Length (millimicrons)
92 A
86 B
83 C
115 A
118 B
114 C
111 A
121 B
110 C
53 A
82 B
54 C
38 A
60 B
66 C
71 A
68 B
49 C
Hg
404.7
0.0000
0.0000
0.173
0.716
0.838
0.862
435.8
.0000
.0000
.340
.728
.724
.815
491.6
.0000
.0026
.500
.277
.162
.560
546.1
.0000
.1053
.211
.0130
.0031
.194
578.0
<.0001
.268
.0554
.0060
.0022
.177
380
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.028
0.028
0.028
0.477
0.468
0.472
0.783
0.783
0.783
0.795
0.795
0.795
90
.070
.069
.070
.616
.604
.610
.845
.841
.840
.845
.845
.846
400
.139
.138
.139
.695
.689
.693
.852
.845
.844
.862
.861
.862
10
.207
.205
.206
.738
.731
.737
.830
.824
.824
.854
.854
.855
20
.264
.262
.264
.749
.742
.749
.791
.786
.786
.834
.834
.834
30
.317
.315
.317
.742
.736
.742
.755
.750
.750
.822
.822
.823
40
.360
.358
.359
.726
.721
.726
.709
.705
.705
.810
.810
.812
450
.0000
.0000
.0000
.407
.406
.407
.699
.693
.698
.657
.653
.653
.799
.799
.801
60
.0001
.0001
.0001
.451
.451
.452
.655
.649
.653
.593
.589
.589
.780
.781
.783
70
.0003
.0003
.0003
.481
.481
.481
.569
.564
.567
.473
.471
.473
.738
.739
.741
80
.0008
.0008
.0008
.497
.497
.497
.440
.437
.439
.318
.318
.320
.664
.665
.667
90
.0022
.0021
.0021
.501
.501
.501
.302
.300
.301
.181
.181
.182
.569
.569
.570
500
.0056
.0054
.0055
.486
.486
.485
.201
.200
.200
.1010
.1015
.1023
.497
.497
.497
10
.0132
.0128
.0130
.450
.450
.450
.1120
.1115
.1112
.0443
.0447
.0449
.397
.397
.397
20
.0266
.0261
.0265
.395
.394
.395
.0551
.0550
.0546
.0161
.0163
.0163
.302
.302
.301
30
.0494
.0483
.0489
.330
.328
.329
.0222
.0222
.0220
.0048
.0049
.0049
.220
.220
.219
40
.0814
.0798
.0807
.255
.253
.255
.0131
.0132
.0131
.0027
.0028
.0028
.184
.185
.184
550
.1237
.1218
.1228
.185
.183
.185
.0152
.0152
.0150
.0042
.0043
.0043
.210
.211
.210
60
.174
.172
.173
.1289
.1268
.1289
.0210
.0210
.0208
.0091
.0092
.0092
.257
.257
.257
70
.0000
.226
.224
.225
.0844
.0824
.0844
.0146
.0147
.0145
.0067
.0069
.0069
.241
.241
.240
80
.0001
.0000
.280
.278
.280
.0525
.0509
.0526
.0045
.0046
.0045
.0016
.0017
.0017
.160
.160
.159
90
.0000
.0002
.0002
.327
.325
.326
.0309
.0296
.0309
.0011
.0011
.0011
.0003
.0003
.0003
.0964
.0962
.0954
600
.0001
.0005
.0004
.368
.366
.367
.0174
.0165
.0174
.0008
.0008
.0008
.0002
.0002
.0002
.0951
.0950
.0938
10
.0013
.0019
.0013
.402
.400
.401
.0099
.0093
.0099
.0008
.0008
.0008
.0003
.0003
.0003
.1059
.1058
.1047
20
.065
.022
.015
.428
.426
.428
.0055
.0051
.0055
.0006
.0006
.0006
.0004
.0004
.0004
.1090
.1090
.1082
30
.38
.23
.18
.446
.444
.446
.0030
.0027
.0030
.0004
.0004
.0004
.0003
.0003
.0003
.1036
.1035
.1025
40
.60
.65
.61
.459
.457
.458
.0017
.0015
.0017
.0003
.0003
.0003
.0002
.0002
.0002
.0936
.0935
.0923
650
.678
.798
.785
.469
.467
.468
.0009
.0008
.0009
.0002
.0002
.0002
.0003
.0003
.0003
.0980
.0980
.0970
60
.717
.833
.823
.475
.473
.474
.0005
.0004
.0005
.0004
.0004
.0004
.0008
.0008
.0008
.132
.132
.131
70
.738
.844
.834
.478
.476
.477
.0002
.0002
.0002
.0009
.0009
.0009
.005
.005
.005
.21
.21
.21
80
.754
.852
.841
.479
.477
.479
.0001
.0001
.0001
.0021
.0021
.0021
.034
.035
.036
.36
.36
.36
90
.764
.856
.846
.477
.475
.477
.0000
.0000
.0000
.0045
.0045
.0044
.16
.16
.16
.55
.55
.55
700
.769
.858
.848
.474
.472
.473
.008
.008
.008
.40
.40
.40
.71
.71
.71
10
.772
.859
.850
.468
.467
.468
.009
.009
.009
.65
.65
.65
.810
.810
.811
20
.770
.858
.850
.460
.459
.460
.0085
.0085
.0085
.798
.795
.795
.851
.852
.853
30
.768
857
.849
.450
.449
.450
.008
.008
.008
.860
.857
.857
.868
.868
.869
40
.764
.855
.848
.439
.438
.439
.0075
.0075
.0075
.885
.883
.883
.873
.873
.873
750
.758
.852
.845
.427
.426
.427
.007
.007
.007
.896
.893
.893
.876
.877
.877
60
.751
.849
.842
.413
.412
.412
.0000
.0000
.0000
.0065
.0065
.0065
.900
.896
.896
.876
.877
.877
Luminous Transmission, T2360 (C2=14,350)
0.07341
.07110
.06628
.2526
.2508
.2520
.1218
.1205
.1217
.02246
.02240
.02233
.01299
.01306
.01312
.1889
.1890
.1882
Table VI
Derivation of new A. R. A. transmissions (redefined as A. A. R. transmissions) for the 36 glasses listed in Table IV.
Designation
Relative Luminous Transmission (at 2360°K) as determined at National Bureau of Standards in 1932
A. R. A. Transmission
Color
Ref.
No.
Mean, by 3 Observers with Martens Photometer
Av. Dev. of each Observer from Mean
Computed from Spectral Transmission
Mean, Columns 3 and 5
Dev. from Mean, Col. 3 (or 5) minus Col. 6
As Labeled at Corning
By K. S. G. at Corning
New A. R. A. TransmissionT′ARA
Luminous TransmissionT2360
T2360 Equivalent toT′ARA=TAAR=100.0
Red
C
83
0.9383
0.0051
0.9323
0.9353
±.0030
95.2
97.5
96.2
0.06628
0.06890
B
86
1.0000
1.0000
1.0000
.0000
101.
102.6
102.9
.07110
.06910
B′
88
1.0303
.0021
1.0303
105.
104.6
106.0
C′
91
1.0022
.0213
1.0022
100.
103.1
103.1
A
92
1.0335
.0120
1.0325
1.0330
.0005
100.
106.4
106.3
.07341
.06906
A′
93
.9886
.0103
.9886
97.
102.0
101.7
Means
.0102
.9982
(f=102.89)
102.7
102.7
.0690
Yellow
C
114
1.0056
.0015
1.0047
1.0052
.0004
100.
101.3
101.8
.2520
.2475
A
115
1.0098
.0022
1.0073
1.0086
.0012
100.
101.7
102.2
.2526
.2472
A′
116
1.0051
.0018
1.0051
100.
102.5
101.8
B′
117
1.0038
.0017
1.0038
100.
102.1
101.7
B
118
1.0000
1.0000
1.0000
.0000
100.
101.1
101.3
.2508
.2476
C′
138
1.0011
.0011
1.0011
100.
101.5
101.4
Means
.0017
1.0040
(f=101.29)
101.7
101.7
.2474
Green
C
110
1.0134
.0021
1.0098
1.0116
.0018
102.
103.1
102.6
.1217
.1186
A
111
1.0158
.0019
1.0105
1.0132
.0026
102.
102.7
102.8
.1218
.1185
A′
112
1.0087
.0018
1.0087
102.
102.1
102.3
C′
113
1.0177
.0025
1.0177
102.
103.3
103.2
B′
120
.9952
.0014
.9952
100.
100.6
100.9
B
121
1.0000
1.0000
1.0000
.0000
100.
101.5
101.4
.1205
.1188
Means
.0019
1.0077
(f=101.42)
102.2
102.2
.1186
Blue
A′
52
1.0113
.0029
1.0113
100.
101.4
101.4
A
53
1.0024
.0020
1.0029
1.0026
.0002
100.
100.6
100.6
.02246
.02233
C
54
.9950
.0040
.9969
.9960
.0010
100.
99.4
99.9
.02233
.02235
C′
79
.9924
.0037
.9924
100.
99.7
99.5
B′
81
.9923
.0015
.9923
100.
99.2
99.5
B
82
1.0000
1.0000
1.0000
.0000
100.
100.7
100.3
.02240
.02233
Means
.0028
.9991
(f=100.29)
100.2
100.2
.02234
Purple
A
38
.9942
.0024
.9944
.9943
.0001
100.
101.0
100.7
.01299
.01290
A′
39
.9931
.0032
.9931
100.
101.0
100.5
B
60
1.0000
1.0000
1.0000
.0000
100.
101.0
101.2
.01306
.01291
C
66
1.0051
.0018
1.0046
1.0048
.0002
101.
101.2
101.7
.01312
.01290
C′
67
1.0004
.0025
1.0004
101.
101.5
101.3
B′
68
.9937
.0023
.9937
100.
100.3
100.6
Means
.0024
.9977
(f=101.23)
101.0
101.0
.01290
Lunar white
C′
40
1.0214
.0015
1.0214
101.
101.0
101.9
C
49
.9979
.0024
.9959
.9969
.0010
99.5
100.0
99.4
.1882
.1893
A′
67
.9977
.0022
.9977
100.
98.9
99.5
B
68
1.0000
1.0000
1.0000
.0000
100.
100.1
99.8
.1890
.1894
B′
69
.9946
.0006
.9946
100.
99.5
99.2
A
71
.9972
.0010
.9993
.9982
.0010
100.
99.9
99.6
.1889
.1897
Means
.0015
1.0015
(f=99.75)
99.9
99.9
.1895
1
2
3
4
5
6
7
8
9
10
11
12
Table VII
Relation between values of TAAR and of T2360, which defines the luminous transmission scale established in the 1935 and 1938 A. A. R. signal glass specifications.
Color designation of glass
A. A. R. transmission, TAAR
Equivalent luminous transmission, 1931 I. C. I. standard observer, illuminant 2360°K, T2360
The original derived value was 0.1895 (Table VI). This was at first cut back to 0.189 and was so published in Report 5 and in J. Opt. Soc. Am. 24, 57 (1934). Later work has, however, indicated that 0.190 is a more accurate conversion factor than 0.189.
Table VIII
Comparison of values of T2360 computed for values of TRSA=100.0 from the 1918 specification, with similar values for TAAR=100.0 computed from data on which the 1935 specification is based.
Color Designation
T2360
ΔT2360 (column 2 minus column 3)
Percent change inT2360 (column 4 divided by column 3, ×100)