Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 76
al point of the reflector.A concentrated light source out of focusmay be just as bad as one having little or THE ILLUM1NAT1X(J ENGINEER (fkb.) GU no couceutiatiun. In order to show theenormous effect on the beam produced byproper and improper focussing, thefollowing diagram (Fig. 1) is presented.… … Feet from centre of beam. Fig. 1—Searchlights with Metal Filament lamps Showing effects of proper and improper focussing of lamps.
Lighting
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