A study of direct and indirect illumination
A 1912 engineering thesis by Alexander McDougall Simons at the University of Illinois, measuring light levels from direct and indirect fixtures in rooms and recording the results as hand-drawn plates for faculty examiners. The drawings pair red isolux contour loops over dimensioned floor plans with handwritten point labels, and foot-candle curves plotted on ruled graph paper, offering contour shapes, measurement arrows, and two-color line work on tinted stock.
