Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 106
r. It is necessary to emphasise theimportance of a fairly sharp boundarybetween the main penetrating beam andthe space above it. If the boundary isindefinite and the change from brightlight to darkness therefore gradual, itwill not be possible to direct the brightestpart of a beam upon the legs and… … yr:;///;////////////////////////;///;/////;;;;///;/////;;;?sw,//;////77r//V///7?77T77~,7 Fig. 2. -Illustrating the great variation of intensity at different parts of the cross sectionof the beam necessary to get suitable distribution of illumination. at right angles to the light which strikesthem.…
Lighting
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