. A new method for the measurement of photographic filter factors . PRICE, 5 CENTS Sold only by the Superintendent of Documents, Government Printing OfficeWashington, D. C. WASHINGTON GOVERNMENT PRINTING OFFICE 1921 A NEW METHOD FOR THE MEASUREMENT OFPHOTOGRAPHIC FILTER FACTORS By Raymond Davis ABSTRACT A new method is described whereby the filter factors for orthochromatic and pan-chromatic plates with various filters may be determined with apparatus using asource of light which is corrected in its spectral energy distribution to closely approxi-mate that of average noon sunlight. The apparat
. A new method for the measurement of photographic filter factors . PRICE, 5 CENTS Sold only by the Superintendent of Documents, Government Printing OfficeWashington, D. C. WASHINGTON GOVERNMENT PRINTING OFFICE 1921 A NEW METHOD FOR THE MEASUREMENT OFPHOTOGRAPHIC FILTER FACTORS By Raymond Davis ABSTRACT A new method is described whereby the filter factors for orthochromatic and pan-chromatic plates with various filters may be determined with apparatus using asource of light which is corrected in its spectral energy distribution to closely approxi-mate that of average noon sunlight. The apparatus is essentially a single light source photometer in which two beamsone from either side of the lamp, are reflected so that they fall side by side on thephotographic plate which is used in conjunction with the filter. In the path of oneof these beams the filter is inserted, consequently weakening the light in that lamp, being movable between two of the reflectors, is shifted toward the filter,thus increasing the intensity of the beam on the filter side
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Keywords: ., bookcentury1900, bookdecade1920, bookidnewmethodfor, bookyear1921
