Abstract

A modification of the two step method described by Cyrus Feldman (1) for construction of film calibration curves has simplified and speeded up this task in our spectrographic laboratory. Formerly we used a nomograph or a conversion table (1, 2) to find the value of the Seidel Function for a given transmittance to use in plotting the preliminary curve on linear graph paper. By making use of a specially prepared graph paper whose coordinates are labeled in terms of percent transmission but are proportional to values of the corresponding Seidel Functions, the data for the preliminary curve may be plotted directly (Figure 1), each point representing the percent transmission of the light step versus the percent transmission of the dark step for a given spectral line. These data are then averaged by drawing the best straight line through these points.

On a Method for the Calibration of Photographic Emulsions

Dora G. Kowalewski and Valdemar J. Kowalewski
J. Opt. Soc. Am. 40(9) 621_1-622 (1950)

Effect of Stray Light in Prism and Grating Spectrographs on Emulsion Calibration Curves and Its Significance in Spectrographic Analysis*

Richard N. Kniseley and Velmer A. Fassel
J. Opt. Soc. Am. 44(5) 390-393 (1954)

Emulsion Calibration Scale for Quantitative Spectroscopic Analysis

Harold K. Hughes and R. W. Murphy
J. Opt. Soc. Am. 39(6) 501-504 (1949)

Investigations of the Exposure Scales of Characteristic Curves of Photographic Emulsion Layers*

A. P. H. Trivelli
J. Opt. Soc. Am. 42(7) 467-474 (1952)

Three-Line Method of Obtaining Characteristic Curves for Heterochromous Photometry

Milton Green
J. Opt. Soc. Am. 40(12) 842-844 (1950)