Excerpt from American Cinematographer, Vol. 14: August 1933 (Classic Reprint)
The requirements set forth in this specification demand a type Of equipment far superior to any type of broadside lamp heretofore supplied to the industry.
Mole-richardson, in the design of their new 40 ampere Type no. 29 Twin Arc Broadside lamp, have not only met the specifications, but in a number of instances exceeded them.' The lamp, which is illustrated in the accompanying pho tograph, has been designed for operation at all times with cover glasses to eliminate the possibility of injury to the eyes Of the actors. The diffusion glass which is supplied with the equipment has a high lead content which impedes the transmission Of ultra-violet light, which is the compo nent of arc radiation which causes the inflammation of the eyeball popularly known as Klieg eye. When equipped with cover glasses these lamps produce more than twice the illumination afforded by the old types Of side arcs of simi lar current capacity when Operated Open, and produce a very smooth field Of illumination. The area Of the aper ture of the lamp has been made larger than was that of the old type equipment, so that though the lamps are of higher intensity the illumination is so distributed as to be comfortable to the actors in the set.