Abstract
ALL scientific workers who have had occasion to employ colour-sensitive photographic plates during the last few years will probably have wished at some time to learn some details as to the specially great advances made in their preparation. Also for the efficient use of the plates suitable screens or colour-filters are required to equalise the action of the various colours. Dr. Mees, as director of the firm of Wratten and Wainwright, has had exceptional facilities in dealing with these matters, and in publishing this atlas he is giving others the benefit of his work. The spectra were taken on the spectrum panchromatic series of plates, which, in addition to the usual region of maximum sensitiveness in the violet, show another maximum near λ 6500 in the red, with gradually decreasing action to λ 7500. To obtain as even records as possible, two schemes were adopted:—(1) For the spectra of dyes an equalising screen of special composition, with two cells of mandarin-orange and P-nitrosodimethylaniline, was used with a Nernst lamp; in the case of special dyes the spectra were photographed in two sections for convenience; in front of the slit a wedge-shaped cell was fitted containing the dye solution, with a similar cell filled with pure water the opposite way to compensate for any prismatic effect. By this means the light passed through varying thicknesses of absorbing medium from end to end of the slit, and the resulting spectra show curves bounding the absorption bands which indicate graphically the change in absorption with varying thickness of dye. (2) For the spectra of the colour-filters the wedge cell could not be employed, and in its place a black wedge of specially prepared glass was used. This gave a range of intensity from 1 to 10,000.
An Atlas of Absorption Spectra.
By Dr. C. E. K. Mees. Pp. 74. (London: Longmans, Green and Co.; Croydon: Wratten and Wainwright, Ltd., 1909.)
Article PDF
Rights and permissions
About this article
Cite this article
An Atlas of Absorption Spectra . Nature 82, 336 (1910). https://doi.org/10.1038/082336a0
Issue Date:
DOI: https://doi.org/10.1038/082336a0