Filters for the Reproduction of Sunlight and Daylight and the Determination of Color Temperature

摘要

A large number of filters have been developed for use in photographic sensitometry, colorimetry, and photometry. They are reproducible from specification and may be prepared in the laboratory. The design of the filters has been based upon extensive spectrophotometric measurements of the component solutions and cell, including a study of Beer's law over the ranges of concentrations used, and upon methods of computation giving accurate color matches and relatively good spectral energy matches between the source-and-filter combination and the energy distribution which it was sought to duplicate. Detailed studies have been made of the reliability of the data, the spectrophotometric reproducibility of the chemicals, the permanence of the solutions, their temperature coefficients, and various other factors of importance in the preparation and use of the filters. The paper contains 33 figures and 26 tables, giving among other things the energy distributions and fundamental spectrophotometric and colorimetric data used in the computations, auxiliary spectrophotometric and colorimetric information obtained during the investigation, and the trilinear coordinates of the various source-and-filter combinations and of the Planckian radiator from 1,600 to 20,000K. computed on the basis of the adopted mean sun as the 'neutral' stimulus. (Author)