iiisfflOHfflSi u ,u *1 *2 *0lLlllfllm Ull AIL^lm. frequently seen, must also be reckon- ed among plants with visible sources of light. They do not cost much to keep up, on account of the small amount of current needed (about 30 watt per pli™ yard), but they cost more to set up S Allium! than electric bulbs on account of the transformers and safety apparatus j j J|j| j j"|j necessary. Especial advantages are I 113VIVSHIElfl VH>17 the intensity of the color (particularly L JK P^^piT of the red tubes) and their adaptabi- An jw M If simply carried out and nottoo large, 1 H the Transparency is an inexpensive H form of illuminative advertising. It -v does not cost much to set up or to keep in order, since it is possible to ||[f - illuminate the surface evenly by means of relatively few lamps.The volume of light required depends upon the degree of brightness in the immediate surroundings. If only a minimum volume be required, it may only be necessary to employ about 60 watt per square yard of transparency surface. The average for transparen cies with black text on a white ground is about 160 watt. The same applies to letters of light made of opal glass, or with the light tube shaded with opal glass. Of course the artfully constructed Large-scale Transparencies, and the Architecture of Light devel oped from them, are expensive, particularly in the first instance, for here it is often d case of ob jects with a superficies of many square yards, difficult to make and to mount; but even then the Engeihardt-Brauerei, Berlin (Durchleuchtung) Engelhardt Brewery, Berlin (Lighted from behind) wm soar

Gebrauchsgraphik de | 1931 | | page 37