Light, photometry and illumination : a thoroughly revedof ''Electrical illuminating engineering'' . tion results desired and the distribution of lightfrom the source required to produce those results depend upon: (a) The size of the room. (b) The height of the source above the reference plane. For any given size of room and height of light center one caneasily determine the distribution curve which will give thedesired distribution. It is obvious that any given distributioncurve will give the same proportionate illumination results solong as the relation between the size of the room and the he


Light, photometry and illumination : a thoroughly revedof ''Electrical illuminating engineering'' . tion results desired and the distribution of lightfrom the source required to produce those results depend upon: (a) The size of the room. (b) The height of the source above the reference plane. For any given size of room and height of light center one caneasily determine the distribution curve which will give thedesired distribution. It is obvious that any given distributioncurve will give the same proportionate illumination results solong as the relation between the size of the room and the heightof the light center is kept constant. If now we let mean dimension of roomheight of light center above reference planethen for any value of J there is a given distribution curve whichwill produce the desired distribution of illumination. 260 LIGHT, PHOTOMETRY AND ILLUMINATION Small Rooms.—For lighting a residence room, or small office, itis usually satisfactory to have the central half of the roomuniformly illuminated and allow the intensity near the walls todrop to 1/3 the central 10 864 202 4 0 Floor Line Fig. 153.—Desirable distribution of illumination in a room. 80 Apparent Candle-power120 160 200 240 280 320 330 400


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Keywords: ., bookcentury1900, bookdecade1910, booksubjectlight, bookyear1912