MIL-DTL-43511D
TABLE IV. Example for calculation of spectral transmittance deviation. (cont.) 1/ 2/ 3/ 4/ 5/
Average
Wave
Wave
Trans-
Percent
length
Band
length
mittance
deviation
(nm)
T
N
range
Tn
100(1-Tn/Tc) x Weight = Product
550
0.155
4
520-580
0.155
0.22
10
2.2
560
0.157
570
0.158
580
0.159
5
550-610
0.159
2.31
10
23.1
590
0.160
600
0.160
610
0.160
6
580-640
0.160
3.39
10
33.9
620
0.161
630
0.161
640
0.160
7
610-670
0.160
3.12
10
31.2
650
0.159
660
0.159
670
0.158
8
640-700
0.158
1.67
5
8.3
680
0.157
690
0.156
700
0.153
9
670-730
0.153
1.18
1
1.2
710
0.151
720
0.149
730
0.148
Totals
71
262.5
Notes:
1/ Tc = Total visible transmittance of sample visor, which is 0.155.
2/ T = Transmittance at 10 nm intervals.
3/ Tn = Average transmittance of 60 nm band. The Tn for a given band is the average of
the seven tabulated values within that band except that the first and last values are
divided by 2 and the average computed by dividing the sum of the values by 6.
4/ Average percentage deviation of spectral transmittance within nine spectral bands.
(Average deviation 262.5/71 = (3.7%)
5/ This table is based on illuminant "C".
4.4.9 Chromaticity of class 2 and 3 visors test. The chromaticity coordinates x and y shall be
calculated from spectrophotometric data. Table V illustrates a sample calculation.
TABLE V. Sample computation table of coordinates
1/ 2/ 3/ 4/ 5/
Wavelength
(nm)
x
y
z
T
xT
yT
zT
380
4
20
0.104
0
0
2
390
19
89
0.240
5
0
21
400
85
2
404
0.301
26
1
122
410
329
9
1,570
0.275
90
2
432
420
1,238
37
5,949
0.174
215
6
1,035
430
2,997
122
14,628
0.110
330
13
1,609
440
3,975
262
19,938
0.093
370
24
1,854
11
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