Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 102
)ackground … Fig. 2.—Suggested instrument based oncontrast (Mr. A. Cunnington). could be placed behind the diaphragmbefore the fine linos or type became in-visible, whereas with a low illumination,they would be indistinguishable againsta much lighter background. Tiie vaiia-rions in the background would thus…
Lighting
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