R. C. Hirt, R. G. Schmitt, N. D. Searle, and A. P. Sullivan, "Ultraviolet Spectral Energy Distributions of Natural Sunlight and Accelerated Test Light Sources*," J. Opt. Soc. Am. 50, 706-713 (1960)
A contributory factor to the failure of correlation between outdoor and indoor photodecomposition tests is the difference in the ultraviolet spectral energy distributions of natural sunlight and the various indoor test sources which do not duplicate sunlight and differ widely among themselves.
The ultraviolet spectral energy distributions of natural sunlight and of a variety of indoor exposure test sources have been measured. By use of a ferrioxalate actinometer, the measurements have been put on an absolute basis permitting the intercomparison of the sources. The xenon arc was found to be the best approximation of sunlight in the ultraviolet. For shorter-wavelength ultraviolet (below 3500 A), the combination of fluorescent Sunlamp and Blacklight lamps also approximated sunlight.
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Energy measured by actinometer behind filters (200 A half-width).
Energy incident on filters, calculated (see Appendix).
Heliostat. See footnote 8. (Sky component excluded, measured at solar noon.)
Hanovia Chemical and Manufacturing Company, Newark, New Jersey. (See footnote 9.) (Filter was Corning No. 7740.)
Quartzlampen Gesellschaft MBH, Hanau; G. F. Bush Associates, Princeton, New Jersey (data for unrestricted field of view).
Atlas Electric Devices Company, Chicago, Illinois.
General Electric Company, Nela Park, Cleveland, Ohio. Bulletin LD-1, 1956.
Westinghouse Electric Company, Pittsburgh, Pennsylvania.
Beckman Instruments, Inc., Fullerton, California. Source for Beckman DU spectrophotometer.
A. G. Nester, Bartol Foundation, Swarthmore, Pennsylvania. Source for Cary spectrophotometer.
Table II
Ultraviolet spectral energy distribution of light sources. (Values are in μw/cm2/30-A band.)
Wavelength in A
Sunlight
12/27
Xenon
Xenon filtered
Xenotest xenon
Fade-ometer
Sunlamp S-1
Sunlamp RS
Mercury arc AH3
Mercury arc AH6
Fluores. Blacklight
Fluores. Blacklight filtered
Fluores. Daylight
Fluores. Sunlamp
Projection lamp
Purple- X
Hydrogen arc Beckman
Hydrogen arc Nester
2/11
5/3
7/17
2660
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0.9
⋯
⋯
⋯
1.1
3.8
14.7
6.3
⋯
⋯
⋯
⋯
⋯
⋯
0.61
1.10
2690
⋯
⋯
⋯
⋯
1.1
⋯
⋯
⋯
0.7
2.8
9.7
9.3
⋯
⋯
⋯
⋯
⋯
⋯
0.59
1.09
2720
⋯
⋯
⋯
⋯
1.6
⋯
⋯
⋯
0.6
2.9
8.2
12.1
⋯
⋯
⋯
⋯
⋯
⋯
0.58
1.08
2750
⋯
⋯
⋯
⋯
2.2
⋯
⋯
1.8
0.9
3.9
8.2
14.6
⋯
⋯
⋯
⋯
⋯
⋯
0.56
1.06
2780
⋯
⋯
⋯
⋯
3.3
⋯
⋯
1.8
0.8
4.0
7.9
17.1
⋯
⋯
⋯
⋯
⋯
⋯
0.54
1.04
2810
⋯
⋯
⋯
⋯
4.7
⋯
⋯
2.0
3.9
16.1
11.5
21.2
⋯
⋯
⋯
⋯
⋯
0.04
0.54
1.03
2840
⋯
⋯
⋯
⋯
7.0
⋯
⋯
2.4
0.7
4.3
7.6
20.7
⋯
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⋯
0.9
⋯
0.08
0.52
1.01
2870
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9.5
⋯
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2.8
0.7
4.4
6.0
20.5
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⋯
⋯
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0.08
0.51
0.99
2900
⋯
⋯
⋯
⋯
15.6
1.59
⋯
3.0
4.4
16.3
11.2
27.5
0.5
⋯
⋯
7.5
0.1
0.09
0.49
0.97
2930
⋯
0.08
0.10
0.04
21.4
3.32
⋯
3.3
2.1
11.3
7.0
22.8
0.5
⋯
⋯
10.4
0.1
0.10
0.47
0.93
2960
0.06
0.20
0.31
0.06
25.6
5.58
⋯
3.5
18.2
63.9
22.7
44.2
0.8
⋯
⋯
15.3
0.1
0.11
0.45
0.90
2990
0.12
0.52
0.85
0.10
30.7
8.84
⋯
4.0
16.1
61.3
27.8
57.6
1.0
0.6
⋯
18.7
0.2
0.12
0.43
0.87
3020
0.38
1.87
2.8
0.09
35.4
12.8
5.3
4.3
46.0
163
34.3
60.4
1.0
0.8
⋯
22.9
0.2
0.17
0.42
0.84
3050
1.03
5.2
7.1
0.23
43.4
18.9
13.9
5.0
5.6
80.8
28.7
56.0
1.1
0.7
⋯
25.2
0.3
0.18
0.40
0.80
3080
2.90
10.3
13.0
0.64
52.2
26.3
21.3
5.5
1.4
11.2
6.8
35.5
1.3
0.8
⋯
26.9
0.3
0.24
0.38
0.77
3110
6.9
19.0
22.2
1.58
55.5
31.9
31.4
6.9
61.1
113
8.9
50.1
3.0
1.8
⋯
28.6
0.4
0.38
0.36
0.74
3140
11.4
27.6
32.3
3.1
63.3
39.9
44.6
8.0
130
343
85.9
109.5
7.1
3.1
4.5
30.3
0.6
0.55
0.34
0.70
3170
17.2
38.2
39.9
4.8
65.9
45.3
49.0
8.3
1.7
19.7
20.8
83.9
4.7
2.8
3.5
25.5
0.7
0.83
0.33
0.67
3200
22.8
47.6
50.1
7.2
72.9
53.1
59.4
9.3
1.3
13.8
9.1
49.9
6.9
4.5
⋯
23.7
0.9
1.3
0.31
0.65
3230
28.8
53.4
57.8
9.6
79.4
60.6
68.0
9.6
1.3
12.8
7.1
38.4
9.5
6.7
⋯
21.3
1.1
1.4
0.30
0.62
3260
43.4
76.8
82.8
15.1
81.3
64.4
78.0
11.1
1.3
12.8
6.2
33.0
13.1
9.7
⋯
18.4
1:3
2.4
0.28
0.60
3290
51.7
89.1
97.0
19.4
91.2
74.3
89.8
13.0
1.4
12.5
5.8
29.4
17.5
13.3
⋯
16.6
1.6
3.6
0.27
0.56
3320
53.5
91.2
102.0
21.4
92.9
77.4
99.1
16.5
2.0
13.6
5.9
31.1
22.7
17.9
⋯
14.0
1.8
4.4
0.26
0.55
3350
54.2
89.6
99.5
22.6
94.5
80.2
108
22.5
14.9
66.9
15.9
46.3
27.8
23.0
0.48
11.8
2.1
5.3
0.25
0.51
3380
56.7
93.7
98.5
23.7
99.7
85.8
114
22.5
2.2
13.0
5.2
25.7
31.6
27.6
⋯
10.0
2.3
5.5
0.24
0.49
3410
64.3
105
113
28.8
105
91.7
124
23.1
2.2
11.4
4.3
22.5
35.3
31.0
⋯
8.5
2.7
6.6
0.22
0.47
3440
65.9
102
113
30.0
107
93.8
137
21.6
1.8
9.9
4.1
21.8
39.2
34.8
⋯
6.8
3.0
7.5
0.22
0.46
3470
69.5
107
116
32.2
113
99.7
144
29.2
1.8
9.0
4.0
21.4
42.3
37.7
⋯
5.7
3.4
8.9
0.21
0.44
3500
84.4
117
129
36.2
118
105
153
68.4
1.9
8.1
3.5
19.9
43.1
39.7
0.14
4.7
3.9
10.3
0.20
0.43
3530
87.9
129
143
41.3
124
111
172
314
2.7
9.0
3.1
18.7
42.5
39.9
0.28
3.7
4.2
11.5
0.20
0.42
3560
88.1
125
146
44.3
130
117
178
765
3.0
9.2
3.2
20.3
41.4
38.6
0.42
3.3
4.7
12.7
0.19
0.40
3590
82.9
118
133
41.8
132
120
177
1186
2.9
8.3
3.3
22.6
38.6
35.9
0.42
2.7
5.1
13.9
0.18
0.39
3620
92.9
137
151
48.8
139
126
185
255
3.8
11.6
4.1
35.1
34.7
32.8
0.69
2.4
5.5
15.8
0.18
0.38
3650
106
160
180
61.1
146
133
189
80.3
219
733
133
197
35.8
34.2
7.3
5.9
6.0
16.8
0.17
0.37
3680
118
179
198
69.1
146
133
239
56.7
608
333
146
221
27.8
26.3
1.9
2.2
6.4
18.2
0.17
0.36
3710
118
178
196
71.7
148
135
238
113
4.1
15.5
13.7
113
22.9
21.5
0.82
1.3
6.9
19.4
0.16
0.35
3740
107
156
180
65.2
155
142
232
325
3.4
7.8
7.6
95.1
19.1
17.7
0.96
1.3
7.4
20.6
0.16
0.33
3770
131
193
215
78.9
162
148
244
894
3.9
6.8
5.4
76.3
15.4
14.4
1.10
1.1
8.0
21.8
0.15
0.33
3800
134
195
230
84.0
169
154
306
2007
4.3
7.9
4.7
70.0
12.7
11.4
1.24
1.1
8.6
22.5
0.16
0.33
3830
108
158
184
70.2
173
158
310
3427
3.9
6.0
4.2
66.5
9.6
9.4
1.37
0.6
9.2
22.6
0.15
0.32
3860
120
177
196
78.5
177
161
294
5150
3.9
5.1
4.1
68.2
7.2
6.9
1.65
0.6
10.2
22.0
0.15
0.33
3890
137
198
223
89.4
180
164
305
4346
6.0
12.0
4.3
69.6
5.9
5.0
1.93
0.5
10.7
20.6
0.14
0.30
3920
135
199
224
90.1
187
171
300
142
7.1
16.1
4.9
68.9
4.9
3.9
2.00
0.5
11.3
19.2
0.13
0.28
3950
116
166
202
85.0
194
177
366
85.0
4.1
4.1
3.9
68.9
3.7
2.7
2.48
0.5
11.9
16.9
0.13
0.27
3980
163
232
265
113
198
181
400
76.0
5.4
5.4
3.8
69.2
2.8
1.9
2.60
0.5
12.6
13.6
0.13
0.28
4010
230
312
303
160
195
178
306
71.2
5.1
5.1
4.1
79.0
2.3
1.4
2.77
0.5
13.2
12.2
0.13
0.27
4040
232
312
378
166
188
172
304
99.6
68.8
202
57.8
303
9.8
5.7
14.1
6.4
13.8
8.7
0.13
0.26
4070
225
313
364
160
192
175
330
200
68.1
223
85.2
446
5.8
2.9
⋯
5.8
14.5
6.1
0.12
0.28
4100
236
320
386
175
196
179
363
343
12.4
49.3
16.5
213
1.6
0.5
4.17
0.5
15.4
4.5
0.13
0.24
Table III
Ultraviolet energy measured in a fluorescent exposure unit compared to calculations on a single tube.
Test conditions (3 in. distance to turntable)
Measured total ultraviolet energy by actinometer cell (μw/cm2)
Calculated total ultraviolet energy for 60°, 1 tube (μw/cm2)
Energy measured by actinometer behind filters (200 A half-width).
Energy incident on filters, calculated (see Appendix).
Heliostat. See footnote 8. (Sky component excluded, measured at solar noon.)
Hanovia Chemical and Manufacturing Company, Newark, New Jersey. (See footnote 9.) (Filter was Corning No. 7740.)
Quartzlampen Gesellschaft MBH, Hanau; G. F. Bush Associates, Princeton, New Jersey (data for unrestricted field of view).
Atlas Electric Devices Company, Chicago, Illinois.
General Electric Company, Nela Park, Cleveland, Ohio. Bulletin LD-1, 1956.
Westinghouse Electric Company, Pittsburgh, Pennsylvania.
Beckman Instruments, Inc., Fullerton, California. Source for Beckman DU spectrophotometer.
A. G. Nester, Bartol Foundation, Swarthmore, Pennsylvania. Source for Cary spectrophotometer.
Table II
Ultraviolet spectral energy distribution of light sources. (Values are in μw/cm2/30-A band.)
Wavelength in A
Sunlight
12/27
Xenon
Xenon filtered
Xenotest xenon
Fade-ometer
Sunlamp S-1
Sunlamp RS
Mercury arc AH3
Mercury arc AH6
Fluores. Blacklight
Fluores. Blacklight filtered
Fluores. Daylight
Fluores. Sunlamp
Projection lamp
Purple- X
Hydrogen arc Beckman
Hydrogen arc Nester
2/11
5/3
7/17
2660
⋯
⋯
⋯
⋯
0.9
⋯
⋯
⋯
1.1
3.8
14.7
6.3
⋯
⋯
⋯
⋯
⋯
⋯
0.61
1.10
2690
⋯
⋯
⋯
⋯
1.1
⋯
⋯
⋯
0.7
2.8
9.7
9.3
⋯
⋯
⋯
⋯
⋯
⋯
0.59
1.09
2720
⋯
⋯
⋯
⋯
1.6
⋯
⋯
⋯
0.6
2.9
8.2
12.1
⋯
⋯
⋯
⋯
⋯
⋯
0.58
1.08
2750
⋯
⋯
⋯
⋯
2.2
⋯
⋯
1.8
0.9
3.9
8.2
14.6
⋯
⋯
⋯
⋯
⋯
⋯
0.56
1.06
2780
⋯
⋯
⋯
⋯
3.3
⋯
⋯
1.8
0.8
4.0
7.9
17.1
⋯
⋯
⋯
⋯
⋯
⋯
0.54
1.04
2810
⋯
⋯
⋯
⋯
4.7
⋯
⋯
2.0
3.9
16.1
11.5
21.2
⋯
⋯
⋯
⋯
⋯
0.04
0.54
1.03
2840
⋯
⋯
⋯
⋯
7.0
⋯
⋯
2.4
0.7
4.3
7.6
20.7
⋯
⋯
⋯
0.9
⋯
0.08
0.52
1.01
2870
⋯
⋯
⋯
⋯
9.5
⋯
⋯
2.8
0.7
4.4
6.0
20.5
⋯
⋯
⋯
⋯
⋯
0.08
0.51
0.99
2900
⋯
⋯
⋯
⋯
15.6
1.59
⋯
3.0
4.4
16.3
11.2
27.5
0.5
⋯
⋯
7.5
0.1
0.09
0.49
0.97
2930
⋯
0.08
0.10
0.04
21.4
3.32
⋯
3.3
2.1
11.3
7.0
22.8
0.5
⋯
⋯
10.4
0.1
0.10
0.47
0.93
2960
0.06
0.20
0.31
0.06
25.6
5.58
⋯
3.5
18.2
63.9
22.7
44.2
0.8
⋯
⋯
15.3
0.1
0.11
0.45
0.90
2990
0.12
0.52
0.85
0.10
30.7
8.84
⋯
4.0
16.1
61.3
27.8
57.6
1.0
0.6
⋯
18.7
0.2
0.12
0.43
0.87
3020
0.38
1.87
2.8
0.09
35.4
12.8
5.3
4.3
46.0
163
34.3
60.4
1.0
0.8
⋯
22.9
0.2
0.17
0.42
0.84
3050
1.03
5.2
7.1
0.23
43.4
18.9
13.9
5.0
5.6
80.8
28.7
56.0
1.1
0.7
⋯
25.2
0.3
0.18
0.40
0.80
3080
2.90
10.3
13.0
0.64
52.2
26.3
21.3
5.5
1.4
11.2
6.8
35.5
1.3
0.8
⋯
26.9
0.3
0.24
0.38
0.77
3110
6.9
19.0
22.2
1.58
55.5
31.9
31.4
6.9
61.1
113
8.9
50.1
3.0
1.8
⋯
28.6
0.4
0.38
0.36
0.74
3140
11.4
27.6
32.3
3.1
63.3
39.9
44.6
8.0
130
343
85.9
109.5
7.1
3.1
4.5
30.3
0.6
0.55
0.34
0.70
3170
17.2
38.2
39.9
4.8
65.9
45.3
49.0
8.3
1.7
19.7
20.8
83.9
4.7
2.8
3.5
25.5
0.7
0.83
0.33
0.67
3200
22.8
47.6
50.1
7.2
72.9
53.1
59.4
9.3
1.3
13.8
9.1
49.9
6.9
4.5
⋯
23.7
0.9
1.3
0.31
0.65
3230
28.8
53.4
57.8
9.6
79.4
60.6
68.0
9.6
1.3
12.8
7.1
38.4
9.5
6.7
⋯
21.3
1.1
1.4
0.30
0.62
3260
43.4
76.8
82.8
15.1
81.3
64.4
78.0
11.1
1.3
12.8
6.2
33.0
13.1
9.7
⋯
18.4
1:3
2.4
0.28
0.60
3290
51.7
89.1
97.0
19.4
91.2
74.3
89.8
13.0
1.4
12.5
5.8
29.4
17.5
13.3
⋯
16.6
1.6
3.6
0.27
0.56
3320
53.5
91.2
102.0
21.4
92.9
77.4
99.1
16.5
2.0
13.6
5.9
31.1
22.7
17.9
⋯
14.0
1.8
4.4
0.26
0.55
3350
54.2
89.6
99.5
22.6
94.5
80.2
108
22.5
14.9
66.9
15.9
46.3
27.8
23.0
0.48
11.8
2.1
5.3
0.25
0.51
3380
56.7
93.7
98.5
23.7
99.7
85.8
114
22.5
2.2
13.0
5.2
25.7
31.6
27.6
⋯
10.0
2.3
5.5
0.24
0.49
3410
64.3
105
113
28.8
105
91.7
124
23.1
2.2
11.4
4.3
22.5
35.3
31.0
⋯
8.5
2.7
6.6
0.22
0.47
3440
65.9
102
113
30.0
107
93.8
137
21.6
1.8
9.9
4.1
21.8
39.2
34.8
⋯
6.8
3.0
7.5
0.22
0.46
3470
69.5
107
116
32.2
113
99.7
144
29.2
1.8
9.0
4.0
21.4
42.3
37.7
⋯
5.7
3.4
8.9
0.21
0.44
3500
84.4
117
129
36.2
118
105
153
68.4
1.9
8.1
3.5
19.9
43.1
39.7
0.14
4.7
3.9
10.3
0.20
0.43
3530
87.9
129
143
41.3
124
111
172
314
2.7
9.0
3.1
18.7
42.5
39.9
0.28
3.7
4.2
11.5
0.20
0.42
3560
88.1
125
146
44.3
130
117
178
765
3.0
9.2
3.2
20.3
41.4
38.6
0.42
3.3
4.7
12.7
0.19
0.40
3590
82.9
118
133
41.8
132
120
177
1186
2.9
8.3
3.3
22.6
38.6
35.9
0.42
2.7
5.1
13.9
0.18
0.39
3620
92.9
137
151
48.8
139
126
185
255
3.8
11.6
4.1
35.1
34.7
32.8
0.69
2.4
5.5
15.8
0.18
0.38
3650
106
160
180
61.1
146
133
189
80.3
219
733
133
197
35.8
34.2
7.3
5.9
6.0
16.8
0.17
0.37
3680
118
179
198
69.1
146
133
239
56.7
608
333
146
221
27.8
26.3
1.9
2.2
6.4
18.2
0.17
0.36
3710
118
178
196
71.7
148
135
238
113
4.1
15.5
13.7
113
22.9
21.5
0.82
1.3
6.9
19.4
0.16
0.35
3740
107
156
180
65.2
155
142
232
325
3.4
7.8
7.6
95.1
19.1
17.7
0.96
1.3
7.4
20.6
0.16
0.33
3770
131
193
215
78.9
162
148
244
894
3.9
6.8
5.4
76.3
15.4
14.4
1.10
1.1
8.0
21.8
0.15
0.33
3800
134
195
230
84.0
169
154
306
2007
4.3
7.9
4.7
70.0
12.7
11.4
1.24
1.1
8.6
22.5
0.16
0.33
3830
108
158
184
70.2
173
158
310
3427
3.9
6.0
4.2
66.5
9.6
9.4
1.37
0.6
9.2
22.6
0.15
0.32
3860
120
177
196
78.5
177
161
294
5150
3.9
5.1
4.1
68.2
7.2
6.9
1.65
0.6
10.2
22.0
0.15
0.33
3890
137
198
223
89.4
180
164
305
4346
6.0
12.0
4.3
69.6
5.9
5.0
1.93
0.5
10.7
20.6
0.14
0.30
3920
135
199
224
90.1
187
171
300
142
7.1
16.1
4.9
68.9
4.9
3.9
2.00
0.5
11.3
19.2
0.13
0.28
3950
116
166
202
85.0
194
177
366
85.0
4.1
4.1
3.9
68.9
3.7
2.7
2.48
0.5
11.9
16.9
0.13
0.27
3980
163
232
265
113
198
181
400
76.0
5.4
5.4
3.8
69.2
2.8
1.9
2.60
0.5
12.6
13.6
0.13
0.28
4010
230
312
303
160
195
178
306
71.2
5.1
5.1
4.1
79.0
2.3
1.4
2.77
0.5
13.2
12.2
0.13
0.27
4040
232
312
378
166
188
172
304
99.6
68.8
202
57.8
303
9.8
5.7
14.1
6.4
13.8
8.7
0.13
0.26
4070
225
313
364
160
192
175
330
200
68.1
223
85.2
446
5.8
2.9
⋯
5.8
14.5
6.1
0.12
0.28
4100
236
320
386
175
196
179
363
343
12.4
49.3
16.5
213
1.6
0.5
4.17
0.5
15.4
4.5
0.13
0.24
Table III
Ultraviolet energy measured in a fluorescent exposure unit compared to calculations on a single tube.
Test conditions (3 in. distance to turntable)
Measured total ultraviolet energy by actinometer cell (μw/cm2)
Calculated total ultraviolet energy for 60°, 1 tube (μw/cm2)