Light, photometry and illumination : a thoroughly rev. ed. of ''Electrical illuminating engineering'' (1912)
Barrows, William Edward, 1878-1960 · New York ; London : McGraw-Hill Book Co. · leaf 290
Fig. 165.—Relative distributionof light from a distributing-typeindirect reflector. Fig. 166.—Relative distributionof light from a concentrating-typereflector for indirect lighting. point directly underneath the reflector. The test was made ina very large room with a ceiling 13.5 ft. high and the…
Light · Photometry · Electric lighting
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