Document mB4x0QjZGeZJ1V76EBo2B2Z2Q

I 786 S. K. GUTH AND E. A. LINSDAY LIGHTING FOR SEEING ,787 ^colored proof viewed under light of a complementary color has a greater contrast ^w,ith;its bac..k.ground ,1; t. These illustrations serve to give some idea of the many places where supple mentary lighting for inspection of difficult seeing tasks helps insure easy accurate fsepjng. In general, the technique for a certain job is developed after careful study ipf*\the problem. The application of fundamental principles in the control, color "quality, and quantity of illumination contributes a great deal to the elimination' /oflthc seeing "bottlenecks" that, in many cases, are the most troublesome features loi m mufacturing processes. ' -c. Figure 39. An example,,of a large amount of ma^'^t`Pj C0>i^Prjeclln C1 t. n, f 1 ----- --------------------------- l((Sj :%3 XI. Infrared Radiation *iThe actual amount of infrared radiation from sources of artificial light in ,typical lighting installations is far below the levels that will have harmful effects upon human beings. At worst, it produces discomfort and annoyance because of .its'heating effects. No significant differences in visual functions were found when most of the infrared radiation was filtered out of light from tungsten filament amf>s.65 If the general heating effects are objectionable or undesirable, fluorescent MgjMing' can be used to provide hundreds of footcandles before such effects are n^iceable on the skin.30 JH'Some industrial processes involve high-energy levels of infrared radiation. Hjggg-wave infrared radiation is readily absorbed by the surface tissues of the Sy; Therefore, these rays cannot inflict deep injuries. Overexposure produces fL.imraediate_dis,coinIort^Jwhich-generally-.-provides-adequate-war-ning. How- __ , the eyes may suffer from continual exposures to'infrared that is below the tgl that causes general discomfort. There is some evidence that this may result Mcataraot. Eyes should be protected by suitable gli'sses from intense direct ffiiation. Fortunately, in most situations where overdxjostire of the eyes to ra- 'fgjaon may occur, visible radiation also is so intense''ifsr'to require protective Jiggles. ii'1 1 -W --_.i....... , I ..,11,^ . -------- snn ' VV* Figure 40. ColOtej light used'for inspecting color proofs in the printing inc ustry-i_g^ of a color complementary to the printing ink makes the ink appear dark grey jg background; for example, using blue light on yellow proofs. 1. d .Si v7 XU. Ultraviolet Radiation 1 l ! Since ultraviolet radiation is readily absorbed in.ihuffian tissue,' it produces , perficial injuries, chiefly to the skin and eyes. Ho^gye^-mpstwlamps-used for BJ^aHighting.:purposes'emit^littl'ror no' ultra'vi'ol'et'TadiatrdS'saTfiat' ih' typical Sting installations there are no harmful effects.06 On the other hand, there are ertain special-purpose lamps that are designed to emit shorter-wave radiation, ome industrial processes, such as welding, also produce considhmile amounts of jBpradiation,Tnrthese..oasesdtdS(necesary to take certain-precautionr----___________ & The effects of exposure to ultraviolet radiation are similar to sunburn. Since " M. Luckiesh and F. K. Moss, Infrared radiation and visual function, J. Opt, Soc. Amer., 27. 69 (1937). "Effect of fluorescent lighting on the eyes, J. Am. Med. Assoc., 124, 608 (1944). Wri'&y -1, JSnfT"