Table I
Measurement of mercury lamp* by a number of observers with a large (L ) and a small (S ) field.
Screen
Observer Eye Constant Y /B Osram N.B.S. E.T.L. G.E.V.L.
L S L S L S L S
W.E.F. 1.004 14020 14380 15030 15340 14500 14560 14860 14940 A.L.S. 0.964 13870 13990 13860 14110 13590 13960 14070 14330 E.M.W. 1.032 13910 14100 14300 14080 13940 13560 14120 14140 E.Q.A. 0.967 13560 13940 13390 13530 13530 13670 13800 14240 M.G. 0.998 13930 14030 12830 13640 13230 13790 13480 15290 J.F.R. 1.001 13980 14290 13410 13940 13470 14460 13790 16490 C.F.K. 0.677 14000 15120 12860 14810 12910 14730 14110 16150 N.F. 1.079 13780 13920 14450 14770 13780 14020 13670 13420 Means 0.965 13860 14220 13770 14280 13620 14120 13980 14880 Percent gain 2.3% 3.7% 3.7% 6.5%
* Average of three lamps. Results in lumens.
L , 8–10° field.
S , 2° field.
Table II
Comparison of direct comparison and flicker methods of measuring candlepower.
Observer Y /B Eye Constant Green Fluores . 4 lps . Sodium Mercury
Direct Flicker Direct Flicker Direct Flicker Direct Flicker Direct Flicker Direct Flicker
Field Brightness 7 m L 8 m L 10 m L
W.E.F. 1.008 466 447 1.042 927 967 0.957 1436 1416 1.014 A.L.S. 0.964 461 468 0.985 899 912 0.985 1330 1402 0.949 G.K. 1.047 500 451 1.108 967 989 0.979 1520 1425 1.067 A.H.T. 1.055 484 441 1.097 930 971 0.958 1467 1421 1.032 B.T.B. 1.004 480 463 1.037 972 977 0.995 1476 1470 1.005 C.F.K. 0.677 488 625 0.781 955 838 1.140 1446 1656 0.873 J.F.R. 1.001 472 453 1.042 968 1019 0.950 1559 1554 1.003 E.M.W. 1.032 463 447 1.036 918 965 0.952 1556 1469 1.060 E.Q.A. 0.967 477 482 0.990 982 930 1.056 1374 1410 0.974 N.F. 1.072 480 409 1.173 950 1003 0.947 1440 1303 1.105 M.G. 0.998 483 463 1.043 902 925 0.975 1424 1417 1.005 Average 0.984 478 468 1.033 943 954 0.991 1457 1449 1.008
Table III
Candlepowers of a number of different colored lamps as measured with a flicker photometer.
Observer Y /B Eye Constant Fluorescent Lamps Hg Av. 3 lps . Na Av. 3 lps . Hg/Na
Neon 2 lps . Green 4 lps . Blue 8 lps . Pink 8 lps . Pink Blue
Field Brightness 3 m L 3 7 2.8 3.2 10 8
W.E.F. 1.008 700 475 323 407 1.260 1480 1025 1.443 A.L.S. 0.964 674 498 370 394 1.065 1456 978 1.490 G.K. 1.047 719 479 314 399 1.270 1490 1078 1.382 A.H.T. 1.055 736 469 299 407 1.361 1471 1051 1.400 B.T.B. 1.004 690 492 325 398 1.225 1522 1029 1.479 P.D.C. 0.908 616 534 389 380 0.977 1522 952 1.599 C.F.K. 0.677 377 664 468 316 0.675 1733 926 1.871 J.F.R. 1.001 676 482 316 407 1.287 1480 1090 1.358 E.M.W. 1.032 706 475 348 413 1.186 1441 1027 1.403 E.Q.A. 0.967 654 512 379 391 1.031 1448 966 1.500 N.F. 1.072 838 435 330 444 1.345 1485 1131 1.314 M.G. 0.998 694 492 359 393 1.094 1484 1004 1.476 Average 0.989 674 501 352 396 1.128 1501 1021 1.476
Table IV
Candlepower of H-1 lamp using flicker photometer with and without color screen (E.T.L.).
Observer Eye Constant Y /B Using Color Screen Without Screen
W.E.F. 1.008 1491 1430 A.L.S. 0.964 1396 1410 P.D.C. 0.908 1394 1446 E.Q.A. 0.967 1353 1388 C.F.K. 0.677 1475 1715 E.M.W. 1.032 1368 1391 A.H.T. 1.055 1397 1370 G.K. 1.047 1391 1370 Mean 0.957 1408 1441 Mean (without C.F.K.) 0.997 1399 1401
Table V
Spectral intensity, milliwatts per steradian, perpendicular to axis of lamp for the lamps used in these tests.
Fluorescent Lamps
Wave -length Band Green Lamps Pink Lamps Blue Lamps Mercury H–1 Lamp Wave -length Band Neon Lamp
3960–4019 1 .6 71 6 5650–5731 1.5 4019–4079 42 61 149 464 5731–5816 11 4079–4142 3 3.1 97 46.5 5816–5905 93 4142–4209 2 1.4 106 8 5905–5998 83 4209–4280 2 1.1 117 10 5998–6094 142 4280–4431 83 126 403 945 6094–6194 243 4431–4516 1 1.3 138 13.6 6194–6300 138 4516–4605 2 1.4 141 10.3 6300–6412 509 4605–4696 2 1.7 141 10.4 6412–6528 297 4696–4789 4 1.4 135 11.7 6528–6647 138 4789–4892 11 1.5 127 16.4 6647–6772 151 4892–5002 46 1.6 119 25.6 6772–6900 35 5002–5123 132 1.3 108 13.8 6900–7035 189 5123–5252 252 1.9 95 14.2 7035–7182 81 5252–5388 262 3.7 80 24.5 Candlepower* 335 5388–5536 223 86 150 1210 5536–5691 93 36 55 35.0 5691–5863 58 132 67 1160 Sodium 5863–6043 20 224 33 31.2 Lamp 6043–6245 9 306 23 26.9 5409–5589 .7 6245–6470 5 300 16 27.6 5589–5786 31 6470–6705 2.5 224 11 30.5 5786–6001 1965 6705–6960 1.7 136 8 47.7 6001–6244 34.5 6960–7250 .9 69 5 46.0 6244–6515 40 Candlepower* 540 375 360 1470 6515–6816 16.0 6816–7151 14.6 Candlepower* 967
* Calculated from intensity and standard luminosity factors and certain corrections for variations of lamp during successive tests.
Table VI
Measured and calculated values of the candlepowers of a number of lamps.
Candlepower Lamp Measured Calculated Tungsten standard* 1415 1408 Mercury H-1 1501 1470 Sodium 1021 967 Neon 337 335 Fluorescent green 125.2 135.0 pink 49.5 46.9 blue 44.0 45.0
* Mean from standard lamp (color temp. 2850°K) calibrated at N.B.S.
Table VII
Relative luminous intensity of the yellow and the green mercury lines as measured by a number of observers using a flicker photometer.
Observer Eye Constant Y /B Observed Luminous Output Through the Screen
Yellow Green Y /G
W.E.F. 1.008 447 324 1.379 A.L.S. .964 427 319 1.340 A.H.T. 1.055 443 312 1.420 G.K. 1.047 446 314 1.423 C.F.K. .677 451 425 1.061 N.F. 1.072 454 316 1.438 J.F.R. 1.001 472 334 1.410 M.G. .998 431 321 1.340 O.U. 1.004 450 331 1.360 W.J.M. .997 435 316 1.377 G.R.B. 1.113 426 280 1.521 V.J. .951 439 348 1.263 P.D.C. .908 428 326 1.310 E.Q.A. .967 421 310 1.356 B.T.B. 1.004 449 337 1.357 R.W.U. 1.058 420 301 1.393 W.E.F. 1.009 440 316 1.393 A.L.S. .964 420 313 1.341
Mean .989 1.360