However, the 1908 specification does state that “The manufacturer must submit samples of glasses showing the extreme limits of colors which it is proposed to furnish. These shall bear labels showing the photometric values ….” There were also given in the specification certain qualitative restrictions tending to prevent glass of undesirable color from being used. This original specification is considered further in Section IV, below.
Details of these measurements are given in , Signal Section Proceedings, A. R. A.30, 384 (1933).
Memorandum entitled, Plan for Reexamination and Duplication of A. R. A. Color Standards and Limits now Deposited with Corning Glass Works; this memorandum was prepared by H. P. Gage and represented the conclusions of the subcommittee of Committee VI, A. R. A. Signal Section, meeting at Corning on October 3, 1930.
Standardization of railway signal glasses—Reports on measurements and investigations undertaken by the Colorimetry Section of the National Bureau of Standards at the request of the Signal Section, American Railway Association. Reports Nos. 1 to 5, K. S. Gibson and Geraldine K. Walker; published in Signal Section Proceedings, A. R. A.30, 384 (1933): . The transmission (A. R. A. scale) of 36 specimens of signal glass relative to transmission of 6 A. R. A. standards marked “J. C. Mock 10–3–30,” a report on measurements made at Corning Glass Works, December 9–11, 1930. (June1, 1932.) . Measurements of spectral and luminous transmissions leading to the derivation of new A. R. A. transmissions for the 36 glasses listed in report No. 1. (October24, 1932.) . Spectral and luminous transmissions and derivation of new values of A. R. A. transmission for the 22 “limit” glasses selected by Committee VI, A. R. A., at Corning, November 5–6, 1931 and engraved “J.C.M. 11–6–31.” (December2, 1932.) . Chromaticities and luminous transmissions, with illuminants at 1900°K and 2848°K, for the 22 “limit” glasses described in Report No. 3. (January30, 1933.) . Tentative specifications for railway signal colors. (April27, 1933.) Reports Nos. 6 and 7, K. S. Gibson, Geraldine Walker Haupt, and H. J. Keegan; published in Signal Section Proceedings, A. A. R.36, 136 (1939): . Examination of 65 duplicate limit glasses. (July26, 1934.) . Colorimetric data leading to specification 59–38 for kerosene hand lantern globes; comparison of specifications 59–38, 69–38, and 69–35; certification of duplicate lantern glasses. (September28, 1938.)
A. A. R. Signal Section Specification 69–38, Signal Glasses (exclusive of kerosene hand lantern globes); approved, 1938. The 1935 issue of this specification appeared in that year under the number 69–35. The differences between 69–35 and 69–38 are very slight, and no change at all was made in the transmission scale. The present transmission scale will be considered to have been established in 1935, although the data on which it is based were obtained and reported in 1930–32.
A. A. R. Signal Section Specification 59–38, Kerosene Hand Lantern Globes; approved, 1938. The present A. A. R. scale of transmission is incorporated in Specification 59–38 (so far as applicable) as well as in 69–38. Both specifications 59–38 and 69–38 may be obtained from Mr. R. H. C. Balliet, Secretary, A. A. R. Signal Section, 30 Vesey Street, New York, N. Y.
Proceedings, International Congress on Illumination, Saranac Inn, N. Y., September, 1928, p. 834.
R. Davis and K. S. Gibson, “Filters for the Reproduction of Sunlight and Daylight and the Determination of Color Temperature,” Nat. Bur. Stand. Misc. Pub. No. 114, Table 2 (1931), M 114. However, the values there given do not extend above 720 mμ. Values from 730 to 760 mμ were used as published in Report No. 2.
Proceedings, Sixth Meeting, I. C. I., Geneva, p. 67. These adopted values are those recommended by Gibson and Tyndall (“Visibility of Radiant Energy,” Sci. Pap. Nat. Bur. Stand. 19, 131 (1923), Table 3, S 475) and are incorporated in the so-called 1931 I. C. I. standard observer (Proceedings, Eighth Meeting, I. C. I., Cambridge, p. 19 (1931). D. B. Judd, “The 1931 I. C. I. Standard Observer and Coordinate System for Colorimetry,” J. Opt. Soc. Am. 23, 359 (1933)).
H. J. Keegan assisted the authors in these observations.
In the preceding parts of the paper the various transmission scales to which reference is made in the present section have been mostly treated as various versions of the same scale. It is more convenient in this section to consider them as separate scales.
That is, hypothetical glasses having values of TRSA or TAAR=100.0.
Presented at the Ninth Annual Meeting of the Railway Signal Association, Niagara Falls, New York, October 10–12, 1905.
Report of Committee on Colorimetry for 1920–21, L. T. Troland, Chairman, J. Opt. Soc. Am. and Rev. Sci. Inst.6, 527 (1922).
Proceedings of the 8th Session, Cambridge, p. 19 (1931).
This will be treated in the next paper.