Light Vision And Seeing By Matthew Luckiesh Signed By Author hy Oe of eer Me Lae Sag - a4 are we Led oe bogus ee : ; eee cars S rs 7 res Tie $5 oe ea Stat ~ ke w e fA 2, a al . : eis : . - r a, 7 <= = : 7 - Tt Ades : = r CF MES yee tea PAIR ae Hoc * ; sth Ve aay : , xe : eh, ) : ¥ : = etched ; : ope pals Sed pl ea Seva Ye Waa eed, Pid Sal Psd apt eh Ga “ she - i ‘ Ses sh TONS ss ; << : to neceatenertet - ps pate Ove cathe shoe goa 3 mf : oan ; wen : : 4 : BSR eevee? ; 5 \ Spb ees AS So big cig siden Sie > CT oi te oe RPP K, ~ wt ry Frat ae ry ‘ . oo : . m : “ : 7 “ 7 “+ +) ster 3 & ; SSA eet = — rH oe Pager 5 ° etal rae 4 Seba tag Pha S rae Muvdcsnuspa tenn e g tga ek ree aN Se ’ ae 5 " ee 4 Ache ¢ Pictes ? at" . ; Ree FOIA on OPEC “3 ASG RPI i ae: 3 Aa nthe ne Fin 5 ete : Kent ap? . beri i Sa Ne > ; cd E Ps ) € est ead Lear tga Cotas wn loon tA EN B6eS grsAR SETS BSN 0CE DN VE o : us PIAS ser asses Sea aie ENE papatesmisel 3 rede d Fa a apes Fein Soe wee MP rod ro cretion 7 eos 3 Pe ey 2 - “ 4 =f - / Ween anse ee ‘ ; of} 7 z ew are x eyo rdt ites am ‘ % ie aie " oe hp “7 Athen Sa an Tite aoe T DAES a a ? 6 2 : ae = 5 Y ha CAF 7 a3 Niae Stee beta tueersaa nen Ort a fet mm i CRs gO a Koes a peh ee eH ARAN Gata tere San S CT eT had n - rs - 2 - * F ee ys) ; s SiBe oe Fs ie wt re are sy ~ ol aes poh Sa ma A iE A OB vee EROS Ne Sarte tention : fo way pr : Ree ta poe plano ea Oe ora beat on Ha er Bree test yer SRA Semcon ete oe are Pet as PAL PaShi gates Ean ev ae Ricken re ie ; rie a Soe ~ Le * pa | £ a wheat OCB ONS Set ’ By Beene tard ean Ea SO Gek es iar arets ¢ paste 4 eee FO TOM OW REN ea cols 2 , 3 ate ' ‘ te tia ie Ot Mi GLO RATS ee er eto tates ena MCA et Lets Sr Ney Fades tatiaiar tins teas 7 , see : f e Veeaea. : pee ela eo PEST 2 pes be , ig i Play ane € OR Ct Reyes : 2 : , foes f f ters , i ‘ l: = Sates : , i a é bo - PEER DIET ED Ba RIED E Be ) a Aarts Byatt Epi 4 l: iiegHt G ieee i von ot 32 sae. ees é bite Hare : ae +s CaF eG r : a pe pas ji c e Tyme. * = i ese Bd et a Tee ie . : r : 3s f - . : nN rs ‘ Yee nee : pen e fs z th? be matty ab te “32 ve BOT EGS ; moss ma - SP «eee 1 Eas Re rs peewee Meets tame hota te = , pyre corte ; ~ 2 t P: 4, . i : “ 5 x . : 3 3 as ~ : f - ¢ MONEY a4 14 oa if Raa RG 4 Sits ; bein ES oat ¥ <3 yrs i BEY pee sh i we sa Toes Ke \ ae) r ite: fs seit ths rseeenan : ; se : om Sooke heeaesre : Asn Aided +, ni ” Ups Meehan oi ane ny jo. Seve ee sili gate. = ire Beate & stare Teeenees owen ASE She Ta sat has ae} eeeltwraiecnty Dias i as : rr we ASS io soos XK Py x 23s a2 nee 2 \ ae oe are 4 Sit orene bari 4i leit st oy Bay ates Peet ht pUORUR! cates ; Mees rit tae tail SEs ‘" east ie eS 2 ¥ fil Dy a Waferalaay i sary = Mae's Grane Mi akties Dereuaen! ont cig NA, eeepc plete hassle ht BEAD RTA tars peels See errenteelar ees 5 i ‘ Dalit hte cherie ae eerie Gacake (ae wee eat i ter ie initied Apr T ANE 3 Sts 35 ates = ie a Bau Eres aan wire elt SEENTOS Tae THA tee beet preg arae et ees <0 ie OES LTR oe TES Seas es pe i tat Fiesta ler) ra: i , ° PHS Che Santon : ‘ ; ye se Sa) iad Levee z Ap Los Te ? : te < mr y ee : : r i he ‘ J + le PR es baka animate 2 * : x r " VP ibe n't 4 . eat eae acted Cir ‘ a : pas ‘ $ J PAO YU secre Fahd 13 Set 2 Yh: Ma Sage Pn ore CS a BS oe: ae is ay ese abens By etl e it rh ” ty Sites art tS cae gee Me ae C yet pe eer Pree: ft Bais paces: ¢ hy : 5 ; Parnes ipo eet! Russie Aether ep ‘ fe iineepavn teh ; ; ne Rie veg Coptarbontentoteaye eerie PTR Pa II a ES ; Mx, erty Sata ae Paiity et % f VED a nr “ x i ‘ > pits - y Rifas) ‘ 1 Me % ‘i a , is Sy ‘ a) font oth : ‘ as i 4 By oy eh al ve SISOS Are A es Si ; bwin st Raesiese ey Are ua Si tn ba 2% ak rt oes a bs at eerkd ette NEE e “oh A di pis a! posure sey ed xi asi! x = PADRES Dian y Sih Oe sea) pale . - Wiranten atc etede elas ay bs 4 tint ay AY Sats ae FEM 3, 25%; eae Poy) se i fh Ti ake f Yess nea “ bisacareyy Se : oad 4 ee : wiped tes ; 5 zi s Met stare ne SA fe is ht ey UREA nel pe pintaeancts Heri osi rie etree ah a Ras ip Manecg este ary Si a penta ‘ : teuipteesend Bp asa ; : 4 phe ; pete . on ; sas aenatsal opaeasies } a BE j ft met Gael Nie Be aeat rte SAR ADT ahs mR Ts Cie Sear wee ei ee aN aT Gas Lei ed Se ip ee = > S53 ots 3 ces ats Tory a tones en A ny Sidr up ms oie SEP SPAS : mad Aire esi re Shai ss Thapar ve rs ate g =F A, z ¥, c ) re " ray as 224). Boe sia POT are! S y b 3 : 7 be - Rs 7 ; f Y bie Dakeae ; ‘ ee : aS d REE BENE 3 ; Plein od akniagk ; ie ; , Perr entire: rhe Aya ore So aia hiner ay Reiss, Eh = a B93) ie 5 PPR ES Mi 2ee=) wi aed ne + ete a 1 Oa He est : Latte Sts a Doe 5 c : : eyo : i wy & 3 St ait iess vy : pita eas , Mie , : : ; , Ac : : y Ne 3 y } eet bce 7 ‘ " 4 5 rea Sims : ; é : te t rata ; ; Ist nt Sean se ghteretie? ‘ ise val Ne i q elites Kec ae diag i Teblerei te pe ‘ Py 3 m } i y : . ae NS Portgeicntm taticeetae pees Brera aie SeReloes i : seared io ena tury eR aes pon tastes ge Beat is PS AU ; Heayems = piers 4 press as te x shee bs Hope Bate AAG wees eee ¥ Piatra tant Bel - ae ety ig ae ser hye ed fa tvenieng sate SS ae < valet ayy E Wer es eto Sea ; soRirec fering tn od GRP Es SE ; pS ——— poz 8 3 sins Se USS f ni! ie % Eyed re j RETEST on s rae f tae TEECRS nie eae Faris mst Glo an bb Lb v45 WA Pe ae 3 wea tet a3 RRS BeEUa Sn kish Unmet si Hee eRe seas pes inss ¥ = . ra * se PONE RY Wea ane lene eee Cr EES TUN RARE RRS Ria - - i = 1 a - « $ ’ 7 , a Vis Y s { j / / . / | i i ‘ | i | . 9 + a ) \ | 3 5 . 4 z \ , } j ns + a RS Pat rR TOL AAS a Wh ok be Rie hinnlverkvcat eines otic Wo piotgsny tne®, ei * pistes 3 rei ipod i, les -} ra asitighe Bree ; iA yah iN Se si pine a: r) Pree rere: Mae, So: Farviecrns es fa A Tat 3 FIstiBe Se ewer orwinte Seater ote sara ae aon paviaisy re bes a aye ae ‘ SUSAR AA ya pt Teabtapirses niente rote ery ieee Reset fits Tx igh f tet sett bats ete yey ts ava ie ih Mi ita aii iS f) ty Sr len ‘ : ii inne i athe i if ft Es ae a: “i Si ‘hr saved hoerbinrins WN. iotin Ue iii ON t nd wa ¥ i Paw Baad > lipo een Ne eben ath aes 3 ne ae Bees Sao beat Kot erat ratty SPs ye Ge Rina EAS Sais Py ere & ah Pedi on {om Bie! aE eel b Maca ape pines oenlyok) boas 7, Fanaa eda ote t. ere on para 4 f ee eS “nat 0 i Oe Bo See Tels -s + Berar vuneaos, TSS oP Sys RS ¥5 St fie ae Fosse} ens! apt Tos aS ey ORS Seapine: ea eaten Raat ae See are Rh tye a HAS was Hy oe Se uA EPS Pp oranauetoh na pom pas eee ai red egos Soe gas: Fa bait il poh Goatees ~ ea iors 2) M e eis eats $3 Sasa ah ws a5. rete an ay % Soe at Misa ‘ iy fe a aoe ‘tm Fetes deat bea S52 VDD af a) Tails: tf é Secs eb, i Aone eye iS Bot coe a 2919. Eras = ce aa: f eameee ey ) cuiigs Oy ff S sft rk = < x RG Sens es Avoay vn ae area! seh SOT saa 7 a “patie Py ea ot 5 Tero ~ TO Aaa EAL PANAL oi hed iba 5 % : : re nn a ceca ee — J . Breese , Bay ¢ ae Sse ea ays ie Ae sth Sieh ih a) Bees Tots nt Re Gee peta Mi i posi fat epee AN nN sateen ey alae & ne uae Gert won ye te CLAN dle ay senate Tea we S ina, be Pathe lhe aes ears ty eae gah a prs Ast Day pa wate a Eseicese LCase Bi Me ] 24 Sapaie ae ac att 3 Ae oad ie OA. 1 Meehan petit Paribas Saye tat Ap) +) bos tiesh Mai Spies nets eR! isaiare be t VEO > Merten 120 VR Se Heestameaen , 2 Det ite) fea aH COS peeeee “hn EY oy Leif ey te pet stetkirtes feat lier i $i esee oye Sizer ees eae Sarak bos Paes ese hp wwe Sea topes a ee ant S. oP or dé say eTids ce s Satay e) pA Sas Serie pene > poo nerrsbeshsect, =) Re ae = eae i) ctndoe (ey se mma Je Tea! = AG ran 1 Tee TES Asis tat aye er { pyle it a5 , ite par oe aed. 7 an at eis hs 5, ae eed Perr py mae <3 ance = Sys mth Sot : eon ; é an aban ie: Seo \ mod aL SEAS EE the tity 23 ray hsm sree : saaerae ; rhs SHSM ty ara eae Reape rea cae tts IPA PRINS Ae f Dali uege ees aes IAGIAD CMG hace: ier s ESE ES a Peay < : z. . : rt . fa cs oe Cie eG et Ne ENS po Sy . t J 7 Ce wee Rete = ae i : : ~ * ° : _ hes Sig ° bitin ‘ f ee 254k yen =e VISION AND SEEING Wa Simplified Presentation of Their Relationships | Their Importance in Human Efficiency and Welfare OTHER BOOKS BY THE AUTHOR READING AS A VISUAL TASK (WITH FRANK K. Moss), 1942 TORCH OF CIVILIZATION, 1940 COLOR AND COLORS, 1938 THE SCIENCE OF SEEING (WITH FRANK K. Moss), 1937 SEEING AND HUMAN WELFARE, 1934 SEEING-—A PARTNERSHIP OF LIGHTING AND VISION (WITH FRANK K. MOSS), 1931 ARTIFICIAL SUNLIGHT, 1930 a BY MATTHEW LUCKIESH, p.sc., p.e. DIRECTOR, LIGHTING RESEARCH LABORATORY, GENERAL ELECTRIC COMPANY NELA PARK, CLEVELAND LIGHT. LIGHT AND HEALTH, 1926 LIGHTING FIXTURES AND LIGHTING EFFECTS, 1925 FOUNDATIONS OF THE UNIVERSE, 1925 PORTABLE LAMPS, 1924 : LIGHT AND WORK, 1924 LIGHT AND COLOR IN ADVERTISING AND MERCHANDISING, 1923 ULTRAVIOLET RADIATION, 1922 THE BOOK OF THE SKY, 1922, 1933 VISUAL ILLUSIONS, 1922 LIGHTING THE HOME, 1920 ARTIFICIAL LIGHT, 1920 THE LANGUAGE OF COLOR, 1918 THE LIGHTING ART, I917 | LIGHT AND SHADE AND THEIR APPLICATIONS, 1916 COLOR AND ITS APPLICATIONS, 1915, 1921 Se on hae ee ee D. VAN NOSTRAND COMPANY, INCORPORATED __ i 250 FOURTH AVENUE, NEW YORK ‘| 7 : 1944 Foreword Food, air and living are simple common words, but their commonplaceness does not conceal their fundamental importance to human beings. ‘The need for food is demonstrated daily and the need for air is quickly obvious. Their relationship to living is equally emphatic; and living is always in bold relief against COPYRIGHT, 1944, BY D. VAN NOSTRAND COMPANY, INC. the inevitability of death. Light, vision and seeing are also simple common words, but their commonplaceness seems to obscure their overwhelming im- De oe, a es ee es ee portance in human activities. Seeing is a great part of the utility es cain a permission 3 and pleasure of living. Total blindness is relatively rare and from the publishers and the author. | 4 only the blind, after having seen, can fully appraise the value of | vision and its essential partner, light. Commonplace inadequacies | in light and in seeing conditions are not generally obvious. Eyes are more patient and less complaining than lungs or stomach. In an age which has witnessed great strides in making life better and work easier, the burdens upon eyes and the responsi- bilities of seeing have greatly increased. In this same period, progress in the production and control of artificial light has been truly enormous. Since Gutenberg laid the foundation for print- ing, the efficiency of light-production has increased a hundredfold and more. However, knowledge of the relationships of light and vision, and of these to the countless tasks of seeing, did not keep pace with the increase in the demands upon eyesight and upon seeing. | Depending upon the use of light, considered in terms of brightness and fitted to the task and to the limitations and abili- ties of the visual sense, seeing may be adequate or inadequate, ~ certain or uncertain, easy or difficult. For any individual the ability of his visual sense is fixed for any given set of conditions; PRINTED IN: THE UNITED STATES OF AMERICA oy ea All Rights Reserved [FOREWORD] but it may be greatly extended by external controllable factors such as light, brightness, lighting and brightness-contrast. Such factors determine the visibility of visual tasks and whether seeing conditions are good or bad. All the controllable external factors determine whether or not the eyes are to be unnecessarily overburdened while performing prolonged tasks of seeing for hours daily throughout lifetimes. And the effects of seeing go beyond the eyes and draw upon the resources of the entire human being. These, and other resources, may be wasted or conserved. Overwhelmingly throughout civilized activities, the efficiency, safety and welfare of human beings depend upon quick, certain, safe and easy seeing. | Owing to the omnipotence of seeing in civilized activities, it is not surprising that various professions, organizations and 1n- dustries, as well as many individuals, are in a position to make seeing easier and thereby decrease the penalties and economic wastes due to generally poor seeing conditions. Naturally each of these can play only a part, but all combined can do much toward conserving vision and other resources. Although the effects of seeing extend far beyond the eyes into the physiological realm of the human being, eventually affecting his behavior and finally his efficiency and welfare, it is sufficient for the purpose of this fore- word to emphasize eyesight and the conservation of vision and other resources. | First, one must recognize the enormous change which civili- zation has brought about in the use of our eyes. From this view- point our artificial world is largely within arm’s reach. Civilized human beings and their eyes are chained like galley slaves to tasks of near-vision for long periods daily. This continues from the time that children enter school, throughout their lives. That this slavery to near-vision is unnatural is axiomatic. What the ulti- mate consequences are no one knows with certainty, but it is obvi- ous that these burdens can be lessened by every means which makes seeing easiér. We are confronted’ with certain facts of statistics which ~ should arouse us. Viewed collectively, eyesight deteriorates from [vi | [FOREWORD | the time that children enter school, and this continues throughout life. The prevalence of eye-defectiveness and of eyestrain dis- orders varies markedly with occupation. These two facts should arouse widespread interest and suspicion. However, they are viewed with apparent complacency by many individuals and some organizations which should not be complacent. Worse still, there is much evidence that eye-defects, particularly of the refractive type, are in effect accepted as inevitable. But is it not just as necessary to prove that these are inevitable as it is to prove that the percentage and degree of eye-defectiveness can be decreased by making seeing easier? Such indictments are mitigated, to some extent at least, when we take into account that only in the last decade or two has an ap- propriate interest been directed toward seeing as distinguished from vision. Seeing is a complex human activity performed with the two essential tools, light and vision. The science of seeing until relatively recently was given little or no attention as such. In fact, the term has been in use less than a score of years. Asa science it is far from.complete, but at least it is now a concept of appropriate magnitude which includes the science of vision and much more. But as yet there are no full-fledged seeing spe- cialists serving our artificial world of civilization which has been built largely by and for seeing. : Eyesight specialists care for eyes in their. offices and sur- geries. Few of them follow eyes into the world of use and abuse. ‘They know much about vision but, for obvious reasons, their techniques and their knowledge do not deal primarily with the activity of seeing and with the countless tasks of seeing in our modern world of seeing. Many eyesight specialists are sincerely interested in making seeing better and easier, but the very nature of their practice gives them little opportunity to serve directly. | They provide eyeglasses which are invaluable to the large and increasing percentage of persons who wear them. These are excellent crutches. They ease some of the burden of modern see- ing but they do not reach beyond to other factors upon which seeing and seeing conditions depend. Eyeglasses do not deal [ vii | [FOREWORD] with the possible causes of some percentage and degree of eye- defects. ie , Some welfare organizations have done well in conserving vision, particularly at birth, and some have done much toward the prevention of accidents to eyes. They can do much more as they accept and follow the dictates of the increasing knowledge of seeing. Medical practice, and all other practices, are contin- ually accepting new dictates from the sciences upon which they are built. It is reasonably certain that the percentage of eye- defectiveness and particularly the degree of eye-defectiveness can be reduced by a better understanding and use of various factors which increase the visibility of prolonged visual tasks and make seeing easier. No profession, organization, or industry has a monopoly on either the responsibility or opportunity for easing the burdens upon human eyes and upon human seeing-machines. There 1s adequate need for the effort and interest of every group and indi- vidual that can help. Civilization as a whole is the trustee of eyesight and of other natural endowments, and of the resources that play a part in seeing or are affected by it. Civilization 1s the trustee of these, for this and for future generations. Eventually it will hold all responsible for whatever neglect of opportunity they have been guilty ~*. This book was written 11 response to many requests from individuals of a variety of interests, for a simplified presentation of the relationships of light, brightness, vision, lighting and see- ing. These are extensive complex subjects and, therefore, their relationships are even more complex. Simplification can be car- ried to any point along the way of diminishing returns. The author has attempted to combine fundamental facts with prac- tical discussions in a way to be helpful to the largest number of persons interested in such obj ectives as better seeing and ideal see- ing conditions, and their effects upon human efficiency and welfare. In order not to carry simplification too far the author has de- pended upon the willingness of readers to meet him part way. Complex data have been presented in the simplest kind of [ vii | [FOREWORD | diagrams. Discussions have been confined chiefly to controllable aids to seeing and to aspects about which something can be done. In many cases readers may wish to delve deeper by consulting original papers; therefore, some references are included. How- ever, more extensive coordinations of the results of researches, and many more references, will be found in two recent books by the author and Frank K. Moss. These are The Science of Seemg (1937) and Reading as a Visual Task (1942), published by D. Van Nostrand Company, New York. - These works and references reveal something of the effort to ascertain how light and other controllable factors can best serve human beings specifically, and civilized progress in general. For more than three decades our researches have been prosecuted along a broad front encompassing all the external factors asso- ciated with vision and seeing. Fundamental factors which influ- ence visibility have been isolated and their relationships estab- lished. A much-needed means of measuring visibility has evolved. The old realm of physiological optics was invaded anew and eventually a new realm of physiological effects of seeing was entered. Old concepts had to be extended and new criteria and techniques had to be developed. Light has played its part ina measured way throughout these researches. In the last analysis, all we see is brightness and color, and these are the progeny of light. Therefore, during these decades of research, the relation- ships of light and vision were systematically studied as never before in continuity and intensity. The result of all this has been the development of much of a new structure of knowledge prop- erly known as the science of seeing. ~ Among other results, the inadequacy of light and the wide- spread poor seeing conditions became more clearly evident and the lighting industry awakened to a greater opportunity, and re- sponsibility, to serve. Other industries, theretofore far apart, discovered that they were natural allies in the cause of better seeing. Professions and welfare organizations found new sup- port in their efforts toward the conservation of eyesight and other human resources. About a decade ago, with the lighting industry [ 1x ] [FOREWORD |. as a nucleus, a campaign was organized under the banner, Better Light—Better Sight. Born as a slogan. for a nation-wide campaign, it rapidly evolved into a world-wide movement. In a decade it crossed the seven seas and invaded the five continents. Founded upon the science of seeing, it touches nearly all civilized activities. Involving the partnership of light and sight, it has attracted a variety of interests. Dealing largely with the essential and gen- erally neglected partner of the priceless gift of sight, it poten- tially appeals to every civilized human being. It is emphatically concerned with his efficiency, safety, comfort and welfare. Over- all, it is helping to combat the widespread indifference to the abuses of eyesight and to the conservation of human resources through better seeing. In consideration of the variety of interests and the practical objectives to which this book is directed, it seems appropriate to dedicate it to this unique movement, BoEah tobe bl Git —— b Bade DeRoOR? Si inG Ei in recognition of a decade of effective endeavor during which it has remained securely founded upon the science of seeing and sincerely dedicated to its objectives. Notwithstanding its original commercial nucleus and spon- sorship, this movement has attracted, and has been greatly aided by, individuals and organizations devoted to human welfare. This is as it should be, for, in a world of private enterprise, the benefits of science reach human beings largely through channels of commerce, involving products and services. This is true whether the product is a vitamin or a lamp, eyeglasses or medical knowledge. This is true whether the service is rendered by an eyesight specialist or a lighting specialist, a profession or an in- dustry. Recognition of these basic facts makes it possible for individuals, organizations, professions and industries, with ap- parently diverse interests, to combine their forces to promote the efficiency, safety, comfort and welfare of their fellowmen. MatrHew LuCKIESH [x] C'ontents POREWORI c.f oe oc oie eg ae CHAPTER LebHis: -CHANGING «WORLD 2. 6:34 We eee ee, Raver Enslaved* by: Near-V ision® 270 fusca sei ah A eae Adaptation, Is Slow. . 2s. Os peah. kaha.) ctiaheeen Ca tematic! 2 Learning to See oo. secaicen ! Lire 5% eel 2 Ee) area eT AO ER ans Eyesight and: Near-Vision™ 2) oo s4.att aie a Pane en se Young and.Old- Byes. oo yi aes. 1 Ra eahe n H emMee a Myesightiand Seeilg =) 3.4). 0.)<) yeh at bane Had he Human: Seeinge Machine: 2.7. orc 32), Fo eg ea II. APPALLING PREVALENCE OF EYE-DEFECTS... . Byes Defectivenessisis: aye eye to does he tae ome Byesieht-iny Worlds Was Tien PU nory, eae eee Gk Mone-Range Investigations Needed4 ee ee Respitesrandvbxercisesiay Mire et OE ee tne igen he lS EGE CAND STG 6 i ioc in os ete ie han eae ee INeed#for*Seeing Specialists”* "ere ee ae at ai ee The Status of Bishting qi. c5 sod eeact nie! daikon a The Cost ofdsightas se isin orn! SS reettaillay ph PLO EN: Phe Science of Lightings; disi(L dins decide ean Ay Diacrammatic: View since teil, ol be s.cesmirecken. « IV. MILESTONES. OF LIGHTING PROGRESS” oo... Mankind: Came Indoors. ho" SE ARLE REE, Mhe:G@andle fun 46 8 ha eS Ok ee, ce rtd Sa aR a Birshcof | VlodernScienCe shir hee dca os ap itcrten neuen be ihe Wamp. C Inimne yer aac, fo8 steel. ee elas Coton: oye hesPipinevotGasi sisi er oe gl, pe ect Birth of the Electrical Age’. . . . . v . i at eae RS Whew GasuViantiong ick oc ha tee he ecco Wares age FlectrieHiaht{Sourcesyet ed te i a PF gia Birth-okMitomeineyeractices grees. 3 UL fee eee oy ase ae Pay Ge ee he Science. of, Seeine fee aes es oF it: Fluorescent amps 3. uhiyas ae 4a ee tee, Challenging the Suni. 4 cee) Garnet. Os [CONTENTS] 3 [CONTENTS | CHAPTER PAGE CHAPTER PAGE avi oW EVA ENERGIE ST AENGS VESTBED weg nese: eek. SI Effect of PupiliSize cat OSA DUAR Te OOS 147 Swit oiente Vlesseneerin es fic woe yl ee ek eee seen es 52 : As Byes Grow Older... watt Gobi a A = 148 Ey es-as Onticals Devices) 25 t. 4; Gok 4 ec ee ee 53 Subnormal Vision 2 to. so sige Renal a ee oO 150 | Hout Hundamental actors, (0) 26h esse ety ae 56 | 2 : peters ae SHAdOWo ee ee Ce ap Re 60 | XI. TEST-CHARTS AND THEIR LIMITATIONS 3 esate... yay ACK OROUNES a sites rane ne Gees rat eae ga ae Rs en: oh 61 : Color-Vision Is Good IWECASUIEO Tra aie eu eee ane eee, 62 He Poe Pcie ‘es : o96 Io Hooge bie pathe: i: i | Bceingets Deceine eile kite Ceci Ripae oe eet Hog 63 Test-Charts and the Range.of Visual Tasks ....... 162 VL BRI GHiNECS Is OMMIBOTENT. © a | Illumination of Test-Charts- MPePe VE att pS Sa OS Ee oie Pe Rea SMe 7 ie CM ek MO eet ai Ned ies 63 Pe XII. MEANING AND MEASUREMENT OF VISIBILITY . . 172 rightness and Diffuse Reflection-Factor (DRF) ..... 70 Borderline Seein | | | are Ra LEE Seon Uo fe, has co Seat PR 2 Cae 173 dhe Fost amper (ky SIRO GIT ALD GEOR 72 a So Deanne Miabiliey 2) ee ee oe We ye 175 Dit Ref and Hootiamberts: . . . . . +/+ ee iia iia | Luckiesh-Moss Visibility Meter. . 2. 2. 2). ehayeuy > 177 | itmuse Retlection-Wactorse eee ie ae 78 Equivalent Type-Size 180 Brightnesses of Outdoor Areas... y Wo. ef 80 Various See-Levels . ees es. at Henne er AN Ao | pee ean ene Ia RP res OgMeL Nal Colts torte ome 82 4 | Hootcandles for quali Visibility 2.1, ="... <2 186 SINGMESS MONIES 8A rete he ee ie eeb ps Tee seengc, 84 | Percent of Maximum Visibility s(t ee ee 187 TT Tan ROLE OF SIZE... 2... = saiee bia Sdoeetd | 7 | Various Uses and Precautions a> Gach ee ne Cae 190 Phycicaland Visual Size: 9... kM A fl eo 88 | SI SEAGE ORISE RINGS) ci: 2? ob as date eee 194 Ie Chet Reading D aya riper: STL TER REEL: . - ae | Physiological iitects.@fOceine vc aire) 1a Seem Mey 1 lely | Bacreroune and Whreshold Size... you: ealall soa 97 | aaa Lats PE athe SUT ar ne rig ee | i oT ase a ae Retina: 11-4 Wibho ni aiemegs ~~ 995. ae Tenseness or Nervous Muscular Tension... .....- - 202 Posi eh Eee wae PaRbeavt enollegieavak SBNamraie | ae ee Phe bleart2Rate Od. 2107 20 SIs oe iMt PD Pr 204. Equivalent Visual and Physical Sizes . ... .. . Oy on | ee pi neice Wiis hase d: Fea OR aH Sizeror Distant ObjCCtsthans wee tae mns Ce peed One oe ee 104 3 fi | BCE TAGS SONS EE oc i VIII. THE IMPORTANCE OF BRIGHTNESS-CONTRAST . . 106 SEO Cee eee a bao’ wadoq to moth“ a Expressing Brightness-Contrast in’Percent (9 ¢¢145 905... 1 the Mista elG a sa aaa hee pce ATION MLS es a! Ditfusely Reflecting Objects and Backgrounds ..... . ey or: Sone aE ate Bag EH ene eee Sieg ae tee ae aan Brightness-Contrast and ‘Fhreshold*Size4. #2 O27 Ot Ns, ae a Br t, : R. Peete Cae Pa Le RCO BREN ra Benes ai ae Miapsof Seeing: OL SUSUR TEBE eS. 116 | | Alene Tech eesecs ey a ee ace ree sae hn lntenestingsoumimary vio, .6y st ee ere ee I ye ent a The abla ee ik Mere 3 Contrast-Sensitivityiac tye eros ey ee Tedd a. fas - ee syne a Dae i A er zs 3 ey IX. IT TAKES TIME TO SEE ..... ; HO hana © Se | Permissible Maximum Brishtnessesae ayaa Meg a | 237 Rie aesses a Time- intervals. se ascii ee ae. 126 Nay LIGHT. AND. COLOR 32 4 2h See. PAs Cae aee ar peter 242 COMO tes Neve Raat pue ee spa palas | . : as and Threshold Sie Ue ee ee ge . Be ereus ees Sa ae Ae on ae Se ibe ae ae es pletion On. odium Light... .-. . RG PO as es ge UIE dg es sya. Bem ode Residual Neeenaces ces ag at ee ele eee he ths Re aes nhancine: Contacte. (eis) eee: om fae CUR ao ROIS Pee ee Wa eh re ee ee Color Wiscriminationic 0.5 a ae ae ay OES. aca 2 2a8 GC eto On Zo BOC THRE Sia 138 Some Psychological Aspects of Light .........- + 251 Se VAS Glare from Various Illuminants. .... . Re ee ert 252 2 ae eee PR Cea anime. Sich ype Pete ras, goes > may 139 Color-Temperature of [luminants. ... . Ae en orang cite Io) Keflection-Factor of Background . . 10... 1... . 139 | Ultraviolet Energy Accompanying Light. . . ..... + 254 Brightnesssand. Contrast 40.01 0 eRe ee ee A 143 Infrared Energy Accompanying Light ......-...-. 255 [ xii ] | | -_ | [ xn | [CONTE NTs | CHAPTER eae PAGE | XVI. EFFICIENCY, SAFETY AND EASY SEEING... . - 255 an Extended Views i iu 7 os Nea Lanlepe eg) ase 0 258 Production iof UsefuluWork 2° 2 SE Teague 261 Productionvand ase of Seeing 6. Oa 265 palety and /Atccidentsir.t Sie ts Shed! CRM Rios Coney 267 Wight and, Safety wait. yi 6 he eA ae ihe bday 267 | Safety and Speedvof Seeing, ai. 02h cue te Be 269 | Light torbasveSecing es ys cc xt 4 aut. Vo eee 270 | Specifying ‘Hooteandle devels ss 14,0) face se kek 272 | | XVI. ONE HUNDREDS QUESTIONS 3 ko ioticd ssp pe. 277 | | REPERDINGES. (7 yee) 2 il SOGe waa Lipen ty 301 INDEX _In the manufacture of this book, the publishers have observed the recommendations of the War Production Board with respect to paper, printing and binding in an effort to aid in the conserva- tion of paper and other critical war materials, [ xiv ] | 4 i 3 ‘ % Baars ty, BEC EO 3 , : Soa error weey pics nhs eS re Bos: Ree; a teaa es nw s é PLATE I—Nature first provided light; then eyes evolved to utilize that light. Thus a partnership was consummated eons ago. Nature endowed human beings richly with senses and mind, and a vast storehouse of hidden secrets. Out of the darkness of ignorance, progress has been nurtured by the light of knowledge. Civilization is at once the beneficiary and the trustee of these endowments, and of the knowledge born of them. | | | CHAPTER I This Changing W orld | , | 5 \ | | | Among all living things man is uniquely distinguished by | his efforts toward self-determination. Originally solely a prod- | uct of Nature, man transcended the animal kingdom in general because he ceased merely to drift with the current in the stream of Nature. Somewhere in the mists of the past he began to fash- jon tools and to apply them. Necessity became the mother of invention. Tools multiplied in variety and complexity. The ap- ____ plications of these greatly increased and also the variety and in- | tensity of activities devoted toward self-determination. Particu- larly in recent centuries civilized human beings by their own achievements have been living in a rapidly changing world! é Necessities are neither absolute nor stabilized. They are relative and they continually multiply with the advance in know]l- edge and in the elevation of the level of living. Wants increase at a greater rate, and luxuries still more rapidly. There is a per- petual evolution. Luxuries become wants and these in turn be- ‘come necessities. All these are continually being born of desires _. for greater production, safety, comfort, ease, convenience and en- joyment. To a great extent necessity and invention are exchang- ing roles. Now invention often becomes the mother of necessity. And this changing world continually increases the tempo of its change! | No person with normal senses and mind can be entirely ob- livious of the enormous change from the natural world of Na- | ture to the artificial, and in some important respects unnatural, | world of civilization. That consciousness arises chiefly from the | benefits obvious to the senses. In the acceptance and enjoyment of these benefits, relatively few persons give serious consideration | to the new problems created by change or to the possible penalties _ | oe. Lt] [LIGHT, VISION AND SEEING | arising from this changing world. Most of these are unobvious, ‘often hidden deeply in statistics or even more deeply in the realms of health and life processes. These penalties may be exacted re- motely from the cause and even. remotely in time. Even profes- sional practices based upon modern science too generally ignore the possibility of deleterious effects of the great changes which man has wrought in his environment and in his activities. Busy with the consequences, little time is available to devote to causes. Relatively few are paid for studying, reducing or eliminating causes. Even modern science is sometimes slow in recognizing the need for studying the hidden effects of change and the need for development of corrective measures or compensating expedi- ents. Nevertheless, research is just as necessary for remodeling man’s artificial world as endless research is essential for the con- tinual building of it. BN SAV ED? BY. Ni. 4.Ro= Vi 1S 5. ON On every hand man has accomplished much in easing the burdens of human muscles. Electrical energy in the past century has done much to transform working and living. Much arduous work has been shifted from men to motors. In uncounted ways electricity provides obvious benefits in comfort, ease, convenience and enjoyment. But while these obvious benefits have come te civilized human beings, man’s skill and knowledge have greatly increased. As a consequence, tools and tasks have greatly multi- pliedsa>: : Owing to the dominance of the visual sense in the usefulness and activities of human beings, visual tasks have multiplied enor- mously in number, variety, duration and severity. Seeing has assumed unobvious burdens as well as obvious responsibilities. And in this changing world no mote complete and universal change has taken place than from distant-vision and casual seeing — in the natural world outdoors, to the oppressive slavery of near- vision and critical seeing in man’s artificial world of cvilization. This is an important change indeed! And one outstanding gift [2] [THIS CHANGING WORLD | of the electrical age—efficient, convenient, controllable artificial light—can do much to ease the burdens upon human eyes and the entire human being. In the past few centuries, a relatively brief period even in the evolution of human eyes and human beings, civilized man- kind has been thrust into a world of near-vision. Countless tools and tasks are within arm’s reach. Critical visual tasks, which re- quire accurate convergence and accommodation of the eyes for prolonged periods, are severe unnatural tasks of seeing. Some of the penalties of this great change in the use of the eyes are more. or less obvious. Some known ones are not obvious. ‘The matter justifies serious consideration in various professional prac- tices dealing with the eyesight, health, safety, efficiency and gen- eral welfare of: human beings. Certainly only through extensive tedious research may we ascertain how various aids to seeing ease the tasks of seeing. Much knowledge is already available but only a beginning has been made in directing it toward easier seeing. : : It is important to ascertain and to utilize the contributions which various aids to seeing may make toward easier seeing. Man has made great strides away from Nature. A general retreat 1s scarcely possible against such forces as the trends of civilization. But easing of the tasks of seeing 1s possible and desirable. The same method—the continual application of new knowledge—which has constructed man’s world, will reduce the burdens of seeing and may eliminate certain penalties of change which accompany the benefits of change. But the great changes in environment, in the use of eyesight, in the responsibilities of seeing, and in the severity of modern tasks of seeing must first be recognized and adequately appraised if advances toward easier seeing are to be achieved on the broad front of civilized progress. And real prog- ress is more a matter of advances in human welfare through con- servation of human resources such as eyesight, energy, health and life of human beings than of mere advances in obvious comfort and convenience. Pod [ LIGHT, VISION AND SEEING] ADAPTATION. IS SLOW Evolutionary processes are too slow to adapt eyesight and human beings to the relatively sudden enslavement by near-vision. There is overwhelming evidence of this throughout Nature and there are some specific facts pertaining to vision. For adults pos- sessing socalled normal vision, visual acuity, or the ability to dis- tinguish fine details of threshold or barely visible size, is measur- ably greater for distant-vision than for near-vision. In general the visual sense operates most efficiently, not only from a muscu- lar viewpoint but from a purely optical viewpoint, when engaged in distant-vision. This is an indictment which hangs over near- vision throughout the entire adult life-span. In view of the im- perceptibly changing processes of evolution, these fundamental facts in favor of distant-vision may be expected to persist for many generations notwithstanding the enormous increase in the use of the eyes for prolonged periods of near-vision during the past few generations. With the processes of evolution ever at work striving to adapt living things to their changing environment, it is probable that the eyes of civilized human beings will eventually develop so as to function more effectively and more easily for near-vision. In ad-_ dition, it is conceivable that our present enslavement by near- vision will be diminished eventually as machinery continues to replace human effort. Such developments as motion-pictures and television may replace near-vision tasks to some extent. How- ever, adaptation by the processes of evolution is of little practical aid or interest to us now. ‘Therefore, it is very important to realize that in a relatively short time the uses of human eyes and the tasks of seeing have changed from easy, casual natural ones to relatively critical prolonged unnatural ones. One aspect of changes in eyesight due to usage may be of more importance than strictly evolutionary changes of the past. This deals with environment and heredity, the scientific analogue of the chicken-and-egg dilemma. Heredity traced backward far enough resolves itself into the accumulative effects of Past en- Lael [THIS CHANGING WORLD| vironment. One can scarcely avoid the conclusion that. eye-de- fectiveness, and probably other unobvious effects, are to some ex- tent the result of abnormal present usage and environment. On the other hand some eye-defects appear to be inherited. ‘There- fore, it is possible that through heredity some of the penalties of abnormal abuse or unnatural use of eyesight under generally poor seeing conditions are passed on to future generations before evo- lutionary processes adapt human eyes and human seeing-machines to the new tasks of seeing imposed by modern civilization. If this is true, progress toward easier seeing becomes of importance even beyond the present. Probably we may have to add to the folly of abusing ourselves and our eyesight an unforgivable abuse of generations as yet unborn. LijiE-A R NiLIN.G.»

Light Vision And Seeing By Matthew Luckiesh Signed By Author

Publication

Turn Of The Century Electrotherapy Museum

Name/Title

Entry/Object ID

Secondary Title

Collection

Acquisition

Accession

Source or Donor

Acquisition Method