Selected Iron Lines on Commercial Spectrographs for Emulsion Calibration

Abstract

The attached tables present some results reported in a paper by the above title at the Symposium on Analytical Chemistry and Applied Spectroscopy, Pittsburgh, Pennsylvania, March 7, 1951. These tables represent homologous groups, each group having a lower energy level common to all the lines within itself. The data has been taken in part from Crosswhite (1). The values of I or log I may be plotted against the %T or density for these individual lines to obtain characteristic curves with a minimum of effort and time in plotting. The column headed quality lists a grade given by Crosswhite. Lines rated A,B, or C are most suitable, while lines rated as D may have from 10-30% self reversal, or some wavelength interference. Column headed resolution indicates the author's observations on spectrograms from a variety of commercial domestic instruments. Spectrograms from grating instruments having a dispersion from 7-3.5A per ram. were observed as well as those from the Bausch and Lomb Littrow Quartz Spectrograph and the Gaertner Two lens Spectrograph (type L254). The results were sufficiently similar so that they have not been tabulated individually, but as two groups, gratings and prisms. Lines marked I are suitably resolved and free from background when the exposure is sufficient to measure satisfactorily the densest line in the table. Rating 2 indicates that the line is probably suitable, but its use will depend upon the particular conditions used, quality of focus, slit width, etc. A rating of 3 indicates the line is not suitable for use due to wavelength interference.