A mechanical device is described that performs automatically the laborious task of reducing a microphotometer spectrum trace to a spectral intensity curve. In performing the conversion the microphotometer trace, divided into sections, is contact printed onto sensitized material using a narrow slit light source and moving the trace and photographic material at different rates of speed past the slit. The slit is parallel to the wavelength axis and, in effect, scans along the density axis. The photographic material moves at constant speed, while the motion of the trace is controlled by a cam whose shape is essentially the photographic characteristic curve. The density curve is converted to a curve of log intensity in one step, and a second step is used to convert to linear intensity. Other uses of the device are suggested.
J. D. PURCELL, "Simple Device for Reducing Microphotometer Traces to Curves of Intensity," J. Opt. Soc. Am. 44, 679-683 (1954)