Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 146
these materials is due largely to directreflection off the shiny first surface.Fig. 18 is very interesting as showingthe gradual transition in diffusingpower as one passes from clear glassto opal. Taking the point immediatelybelow the source we see that the smallest Fig. 11.—Di.-tril)ution curve of… … Fig. 12a.—Distribution curve of bare tungstenlamp (1) and same lamp iu enamelled ironreflector (2). 210 220 200 180 160 140 120 100 80 60
Lighting
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