Spectrographic Calculations with Computerized Emulsion Calibration and Programmable Calculator Computations

Abstract

Photographic spectrographic calculations of intensity ratios and the corresponding element concentrations are performed faster and more accurately with programmable desk calculators than by graphical methods. These calculations are facilitated by applying a transform to microphotometer transmittance readings to make them linear with respect to intensity. This transform has the form log [{(100 – T)/ T} {(a + T)/ T}] where a is the transform constant and T is percent transmittance. A FORTRAN computer program strategy is given for calculating the transform constant from emulsion calibration data and obtaining a linear equation for the emulsion calibration curve. This equation is used to program a desk calculator to convert transmittance readings to intensity ratios corrected for background. A second calculator program computes element concentrations from the intensity ratios.