quirec'l betiaeen the lens and the irnage plate, The shiitter is then opened, and the sensitized surface of the obstruction screen acted 1.lpon by tlie liglit. The area of the screen r being tisually only one thii-d of the area, of the 1)1,-te, the intensity of the light falling oii any ai,-ea of it will be i-istially thrice tl-iat wlijeli AN,ould fall on a like area of the plate. TI)c tiiiie of expostire of tli.e screen will 10 tb.erefore be iyiuch.shorter than on the plate for tlio,,@,ame z@ensitized miterial ' The screen is thed i-emon,ed froni the. ellinera and develope(l.. It is then inanipulated if desired ar)cl. lioles ei:it in the portions of (,reatest 15 densiti, or Ldclitional ol)sti-uctions placed i,ipoii sci,eeii, I)at-ts of the sci-een colored with v,,it.-loits transp,,trent colors ,ueh ,i-, ivill coiidlice to the effectiveness of the sci-eeti. Tli(@ diiiil'niitioii of the detiil withotit jiiate1,-i,,illy c[ii-yjiiiisliiiig the liglitiii- caii be secui@ed by tco,(tt'ng'of iainisli thit is slialitly roti(yliejie(l. Tlle iiiaiiil)tilition of the sci-een n c,tii il,,@o lj(, (,ai,-i-ied oiit witlilii tlie caiiiera. The sci-eeii caii be, itself by iii ob25 -,@ti-lictioll 1)1,teed between it and the leiis wliile illie foi-iiieiis exposecl. This obsti-uctioii Avill the denslty of the obsti-iietion sci-eeii it tije portioiis it affects. This lia,,@ I)e(@ii d(@seiibed above. Tlii6 obsti-iietioii (J sci,,eeii citi ],)(@ si),Itcecl ftoin the sci-een as fai-ts I N,aiitao-eous, the nearer the s I (I lens it is the iiioi-e cliffiised its effect ul)od the screein. Wlii]@e [iiis is I)elno, done the iiy)a(ye pla,f@e ;s 1,)rotect,ed fi-oi-n the liglit passin(, throuoli Z;5 the leiis i(,t i iio, Lipon tlte screei@ Dtiring tl)(@@ exl-)Oslll.e of tile sci-een, this liglit is ,,@t@oppe(I fi-oll) i-eaciiin(y the iiiiaoe plate I)y @71, @n tl)e slia(lel., I)y the backing of tfie the I)O(IY ()I' sei-eeii, oi- ill)e screen it,,,elf. The -,Iititter can 40 I)e closf!d b(,I'oi-c tilie sci@een is removed. The sci.-(,eii tfter it li,,ts beendeveloped, and, If irianiptilated, is replaced in the i'llicl the exposui-e oiven to foi-m the oii tlit@ seirisitive plate. This exposure 4 r) ivi.11 1- liave to I)e soitiewliat, longer than if no selleen lised. If tl-ie sci-een exposed is itsed @is a I)attei-ii onl , then the oDe built up Y, fi-oiyi it. i@,, iiisei-ted iii its place in the shadei-, tl)t@ proc!(,ss beiiig otherwise the sanie. "'O Ad(ltioiiil itiaj)uallv applied obstructions as 69 CIT) li(@ pl(teed on the sci.-een, 5, see Flc,rs. 5 aiid 9, ivliielt can be positioned in view of tlte indicatiojis on the developed screen. I cl",illl1. A sliader foi- cameras, baving an obsty-Lictio)i sci-een coii-iposed of transparent iii,ttei,ial witli obstT.-u(,@tions pliot<)o,,raphically foi-ined 1-hei.-eon. 2. A shadei- foi- caineras liavin- an ob60 sti,-iietion sci-eeii coitiposed of - transparedt inaterial with obstructions p hotographically f<)i -med thereon and auxiliary obstructions foimed by hand. 3. A sbader for cameras, having an obstiuetion screen c itiposed of transparent 65 iiiat ei-ial, liaving tliei-eon obstructions photogiapliically foi-med ancl with diiiiinutions of de nsity in the iiioi-e dense portions of these ob striietions. 4 . A shader for cameras, having an ob7 0 str uction sci,een coinposed of a ti-ansparent iiiat ei-ial liaving tliei-eon obstructions plioto(riapliically foriiied and colored obstructions set witli reference to the photographically foiiiie(I obstl-ucti.oiis. 75 r). The ai-t of i-e,(,,ulatinu locally the shadin @,r of a plioto@,yraph, whi@fi coiisists in form@l '@; pliotogi-a@iiically an obstruction screen "I, I)v exposiii(r a seiisitized screen between the l( @ns ti)d tli@ iii-ia(,e plate of a cainei-a and re- 50 i)io viirio- and dea,elol)izig the saine, replacing tile sci-eeli III 1)0";ition aD(l. takin- the photorn gl,,tplile iie-titive tliroijgli the obstruction sci, eeii. 6. Tli(@ aj,t, o-f j-(,,,,ul,,itiiig locally the sliad- 85 iD y of -li I)Iiot<)(ri,a@l) @vl)lcli consists in forniiii( @y iii obsti-uctioii sci@een by exposing a sensiti zed screen iii the camei-a between the leins aii( I the illlag(' Pltte lDd reiiioving and deAe loplno,, the saiiie, treating the - develope(i go sei' eed to cliiiige iiiaiii,ially its sliadineffect, i@ eplicinf-@, tli(, sci-een 'n osition an I p d taking flite plio[o(-rapliie iiegative tlirougli the T. Ttie I)i-oces-, of locally the o5 of a I)Iiotograpli, wliieli consists in pi-o(lii(@ii.ig i, I)Iioto,,t-,il)liic neuative sci-eell of th,(@ object, ind tlien pl)otogi-apliiiithe object iipoii t.,@eiisitive iiiediujii wliile intet-ceptiiig soji-te of the i-a)@s of lic-lit froiii sai.d ob- ioo ject I)y iiieaiis of s'aid negative sci,eed. 8. I'lie ,tt,t of regtilatiiig locally the shadino, of a plioto(yi-apli, wlii(,Il consists in causi n,-,)- tl)e passin,,, tlii-ou@-nii the lens froiii ttie object to the seiisitize(I iyie(liujyi, to pass io6 algo tbi-oii(.,Ii aii <)bstruction screen pi),otogi-aplileally produced obstructions. 9. 'I'lie ai@t- of i,e(Yulatijnz locally the shad111(r of I pliot6(,i,aph whi(@li consists in causi jig the li(,-Iit passing tbrough the lens froin. iio tlie, <)bject to the sedsitized ifiediujii, to pass also tlii.-oiitb an obstruction screen with, plioto(,,raplilcally prodticed obstructions, said obstriietion screen being placed between the lens -,tiid the sensitized iiiedi-Lim and spaced lir, froiii eacil of them. . In witness whereof I liave hereunto set my gi-iiattii-e. MARK W. COLLET.

Patented Mar. 27 1928. 1 663@996,- UNIT@ED- ST@ATE-S, PATEN.T OFFI,CE. MARK@W. COLLET, OFiPHTLADEEPHtA, kB*NftLVANrA.- SHADER FOR CAXERAB@AND@ IN@ TH'B@,AltT OF RBGZIA*ZRNG- L6CAILLY- ITH-E -SHADI"oir; A@ PMTOGBABN., Application, fLIed- February 4,@ 1919. @ Serial@@Ne. 27i@M., l,n shaders for cameras, and in! the art of i-egiilating locally the shading of a pliotog:t-apli o-f ivliieli the following is asp("cifiel,ition, tlle device and. the pi-actice of the ai-t depei)(I upon the 1)i-inciple that redtiction of tite qtiantity of li@,rlit falling on areas, of ti sensitive plate ot- sensitive filili can@ be effectecl by the 1)1,teing of obstructions beti)(,@ 1)1,ite, or tliei film and the lens lo tllqt will etit off a portion of@ the light that passes tl)j-oti,,Il the lens ti,iid would, if these obstiuctions were iiot so placed, impinge tipon i-)oiiit,s in areas to be sliacied. The o,er)ei,,ai pi.-iticil)le@, (rovernID(,r the position15 ing of sueb oi)st,riietions, theit- consti.-i,jetion,, coiiforn)atiori atiti ariangement@ aild sonie of tlik@ ptirposes of so doing ai-P ,et foi-th in my Pateiit No. 1,254,r)79, dii@te(i Jan. 22nd@ 1,918. 20 My pi-e,,@erit device ,tnd process- enables these obsti@ti(-tions to be positioiied, i-nore readily ,tj)d (.,,ertainly; the obstitictions are pro<lticed plioto,,-t-apliiea,lly, or a pboto@. graplii(, ind'Lettion of tlieii@ ippropi-i-,ite pqsi25 tions, sliapes tn.d the depth of sliading. is prodi.ice@l so tl)at tppropi-i:tte ol).f,,tj,-uctions iiiay be lii(I to effe(.,,t. the clesired shadinr of the, sen,sitive 1,)Iate otfilm 'Witlioiit ne(.,essitatin(,- ,iii aettial itispection of the sbader 30 inside the Consequently, oi-didary staTid,,ti,(l foi.-iiis of filiji caiiiellas; ag well@tt,.@ plate cimei-as rtiay be tised witli the prc-sent (levice,. Fi-o,. I iq an isoinetr@ic Pe,].-qpoetive view of i@5 a iiiei-a NNfiti) the slitidej, contained in it; the belloivs I)ein(, I)i-okeii away to sliow the sb@tidei- ctleij,-Iy. Fi!,,. 2 is ,i .,,ection of the@ shadei@- oii Iiiie 2-@ of Fi-. 4@ Fi,,-.@ 3 is a section of the sb,-tder on line,,,, 3-3'of Fig. 4. @ll) Fi(li 4 is an elevation of tlie@-,Iitder. Fig. @ 5 is an el(-@vatioii of an obstrijetion @ser",,n after exposiii,(@ an(] the al)pen,i-arice of, the pliotoI)! I i Ctl I )T fo T.] f)e(-l obstrticti on @. Fi 6 i,,; 4 5 ,i 'deelei,ationof%anobst rictioi)sereen-witli, ,t ligli'u- pi@oof bieking. Fig., 7 is t,view of, @in obstt-ii(@t'iofi screen' witb t coverin.-@. proflectint), it fi-oii) liglit wben otitsi(le the shadei-. 8 i,,, i,ii elei,@ition of tlie,iipper pai-C of@ the sbacier witli the obstt-uction screeii in,io sei-ted in it. F'g. 9 is a view of an, obqtrue.tion sci-(@en tlitt has been maiiipulated after expostire.i Fi-. 10 ].,s a view of ,t caiiiera liaving tivo shadet-s. Fig. 11 is ,t view of, a, iiiechayiieall,y produced obstriietion screen o6 ttiat cari be tised to modify t-lie photograph- @ ically produced'obstruction screen. Fig. 12 is @t view of obstru,ctions photogiraphic ally 1 produi!ed on- an obst4'uetion,@ screen which ha-ve been, iiiodified by the use of the mechanically produced' ob@tr'uctions s,hown in 60 Fig.@ 11. Fig., 1-3 shows an obstruction screen wlie -m the, li@ht diminishing obstrijetions are col'ored varnishes. Fig. 14 is a side, e]eA,,ation. of the upper part of a shader withv the obstruction screen idserted therein. a An obstruction"s@e:ffect is inore localized an(l.; inte n'sified, the nearer it! is positianed to, the@ sens itive plati@, or filiyi,- and is diffiised in pro portion as it is litoved nettrer tiie lens. Plac ed directly, in- front of', ttie plate or filn' 70 it will, - if deiise enotitxh, stencil the iinage. Plac ed directly it tlie- lens, it will - (liminisli the lig,-.Iiting generally over the- I)Iate with-- out iiiatet!ially, or even sen@@ibly distiirbing the ritio of the li cfiting, of. one area of the 7r) iiiiag e to anotlier aroa thereof from the ratio exis ting. befoi-e the obstriiqtion screen was iiise rted. The screen or sci-eelis tre position ed, I belioie, inost tisefiilly wlien pliteed frou i 50@lo 'to 807o of tbp, dist.gnee froii-i the 13o leiis, 1, to the.plate,- 151 or filin 161.@ All liglit reacliiing.,a@ny, pal-ti(,Ulal, area of, tlie, @sensitive-plate (for'shor-tDess@in - this@disetis, @ioji iN,Iiei-e. plate is expre-,sly iiier)tioned, "oifilm" is to be understood) will lie in@a t3 r) geoi -netricallsolid@having'as one-of the bounding, siit-faces tlieL@area-@of- the lens througli whi cli i).%ss,aLe of ligi.it: is permitted by t-he diap hi-agni,, cre-nerally calw the undiapliivgiued op ening., of@ ilie lens@ t,iiother the, go figuie of tlie7 parti6tilar@ area oft the plate aiid. practitally but not exactly, a surface t@liat@wotild be genei-ated by two right lines, lying. in a p6ne i-otatino,. @n, tlte axis of the lens, oiie end of each line traversing the, 95 uDcliaphraginO@@ opening of, the lens, and the other i, line, boundiDo,-,the area on the, pltite under:eonsideration; the two lines not erk)ssii-ig between@ the, lens and the @late. If a, plat@@ is passed perpendiculai@ to! the loo axis of' the lens, . between tlie, lens and plate its ijiter-,@eetion witli@ the stirfa@ces of tfiis ,;olid will be, ciit - in a figni-e I tliat. will eontain: all-i-ay,,;;,of light passing-.throtigh the plat,40@. 105 lens @ iind @'reacliing@ this, area on -@ the If the two i-ight lines-, iii tlic, above, nwntioi-ted plarw, whose --ixis of revolution @coincides with i the axi.-, of- the, lens el-ostj". tl)en two geonietrical-soli& will be,prodwed having-. coi@cidentf, apices, the, base, of a swid lio

will be tti-@ @trc",,) oii tt-ie plate, the otlier the L,,n@[ia-,)Iiraoriie@t are,@t ol- the lens. If 'i@t 1 -v'@g its basc,, the area on the the soi -i-,L I pla@tc@ is etit 1,)y a 1.)Iaiie 1,,tssed I)erpenclicuL lai-ly to Llie txls of@ tli(-, lens ilie fio,ure foriyif-,d oii this Dl,,Lne by the iiitersectioii of it @iitli the surtaces of this area, be ,t SpaCe 'Llil:Ou(,Yli AAhicli no liglit passes froiii the lens 'L-0 -;'lie plat,-@ that @toes nol@ re,,toh this 10 (11 the plate. TL@c slioc,ter's obstr-Lictloiis ill]Llst covei, pai,t of the arc,,,.t of fio, Lire :tliii,3 foriiied, 01iii-List obstrticlu- tlii@@ p,,isE,,age of Isollie of the light i@,ivs, tlii-otic,,Ii it. @4 1 lia@e d(,vised iy@t(,ails @NIlei@eby this e,,t n bc, accoliti)li@"Ile(I b-y 1)liot6gr,,tpbic aetioii, an@t Llie iiecessai,.y obsLrucLioi-is eltii be pi-odtiel@,d witlioltt ii(,e(I of l@tispetino, tl-it-, iiiteri6i., of t]).(, caiiiert. Tlio sli,,tclci-, 3, coiilaiiis the bsti@,tictioi-i sci-(,,eii 5. The obsti-tiction 0 1 screclil i.s itiacle sc@nsitivg pliotog,,i 'Illy, LPII ic, af.i(l, @A71leLl it lia,s @,po,@.@eOL ,incl develol)ed, it pre,,,,oiit,,,,, @l locilly appe.,,ii-atice, its iiiost @li@i(](,cl ai-(,,as bciii@@- AvIlel-Il@ Cli(@, li(,,Iit 0.5 that b,,i,,i tb(- @ 1, of (lie il re, e v(@@t iiiost ilitieiisely. Tli(, o@'@ these iEi effe(ti@.ed by i@eftectecl froiti ti(,as that al-e @froiii ol@b(,i- iii ilie sub'io jec'@ arid, 'a [lie ' ,,t itly oil aeCoLint of 'Lli(, of the i@ays ,tssiiig @, t-@ p thL'01-1('11 t-Ile lell',, Niill t@e@lteli [lie, saiiie of tllc ol)si.i@tictioll An ol)striietion'-, cai) be c6i),@i@c'tered ,is "I coiyiposite of 35 tile, foritied l@)y the iiitei-se(@tiori of Lli(@, 1) tll(' of tl)e, )Vith tlio t-forej,-tcntioi-iecl ge6i-fietrlc,,t] soli.d,, bai,lilg -.i.t the leiis ,tiid at @Llie v@trioi@[@i "Lil(IlIS Oil [lie P-LLtc, i6i aiid 40 will \,,,ti@y acc,)i,clitilo@ly The sliaclI e@. I e I ,iiigs Nv,lj. 1)(-, iiiii(@ieiitl y d I n'll; to ciiible the o])c@i-c,,(,oi- lo tell A@7l,iLt of tli(@ iiiia(,e 161 1\7ill i,ece@iA,e tlie; ligl)t passiiig [hrotigli the vtii-iotis ,ti,eas oli Llie ob45 Tli(@ obsti-uct-,Io,,is oii the obsLrt,[(ti@i:oii sci-e,,ii tli,,i,t ti-e dii-ectly l@llotogr@,i,pl)ic,,tll pro(Iticed ai-- of-teii siifficieiit y N@,i,L-11OUL otliel, iiii-,I'lplLlatioii of the ol@)silrtiet76ii sci-eep. 60 No Av,,iy oT. sciisitizing the obstrtle'Lloll 5 is ii(,cess,,tpy. A blue l'it'ilit ii@lixliii-e cotipcl oii t celliiloid filiii i-nay foriii the The @- 1,C]@leeii, 5 i)-iay have a backiiig it)-Ipei-viotis to 6, verAT con55 veiiieii.tly oi' bliclc pal)ei,. @ The 3, 3iiay litvf-, stipports, 22, 2P, 23, 23, t6 1-iolci the 9creclID) C)) ,iiiCt the closei-, 4. The screeiis, r), iii,,ty bi@ prot(,,eteci by 9, lip;ht proof cov7, tll"lt is 1),,ick ,),s it is ii-i60 sei.-te(.1 in L'Iie sli,,tclei@ 3. As ,iii exiiiil)le of ,i (le%,elope(i obstruction ,@cil Clil r) ,;,@iows a Iiicrlilv Pol.,- ti.on, 1, sba(lecl ai@ea, 9, and a 17ei,v el ell s d i:ich ]es" Y ]@)oriion, 69, IDCI a m s 65 (1cii,,:,ely obstrLtcte,(] or entirely iinobstrticteci area, 18. Fig. 9 is I illaiiipulated screen. The screen iiiaterial may be etit aivay in an ,irei, 12, of t-lie darkly shaclcd area, 13 ancl tl-ie holes, 15 15 15 15 iiiade I'n the screen iiiatei.ial in ttie very d,,irkly 7(i sli-,ided,pai-t 14. Cutti.ii(y holes in th(, screeii iyiaterial tlirough tlig, 131-iotographictil.), pi-oduced obstructioiis tlic@ J)icttire -at the areas Iffected 1).), tliesti portioiis of the Gereea, aild eii-iphasi7,e, 75 poi@tions of tl-ie picti-ire. Fii)@s. -"LI Lii(I 12 shonv an alixiliary screen@ 85, ancl the dcvelol)ed pliot6o@rtt]@)liically produe(,(l screci-i obtained by using them in the doiil,)]G-,,@h@k(ler can-iei-,,L sliowd ii-i Fig. 10. The ser(@eii, 85, 80 is 1)laced iii the fi-ont, 231, and the biit iiii(levelol)ed screen, 96 is pl,,Leed iii the liol(ler, @,1. The obsti-tiction, 30, (cari-iccl b.@ the ai-iii, 'al) will sli,,ide aii are,,t as 42 (see Fi(-. ll-)) fi-olli lio-l-it fi@om tlle leiis8 - les,,e iiii, the C-1@eils' n ity of tho plioto( call prodilc(@d 6bstructio@l oil it. Tlle shai-py or diffii,@ioli of this (,Iecrease iii dc@iisity will clepeii(-i oil the relative clisttine(@, of the obstrl[ctioii, 30, fi-oiii tlie lens ilicl the ob-iictioii trc,,t of 'lesseiied (]ellGti The , 3 0, iil,,ty be,, in(I it ordilial-ily is AA7it-,Ilili ,t (leiis(,, ai,(,,,.t 31. Usiiig a,ii aiixiliai@y scre(,ii (,,iii i-c@1)1.acc, clitling the obstriiet](11 scileeii o-ft(,,ii. Ob\Tloiisly ina,iiy ol)striictiori slial)(@@, 93 caii b(, 1)1,,teed in tli(@ obstrttetioiiscileel)s. Usiiio- t,lie s(.,i@eeii oi-i(,,-in,,tlly iiiei-t@e(i iii illie, sli,,tdei- 3 as @t fol, forillill@), III ol)- ,tpi:ietioli with @Li-anspai-(,iii. '(ioloi-S oli vat,jous treas, will ofleii 1,)i.,6(ltice f)arLictilai.@- 100 y ly ti,tisti(@ i-eslilts the Nar iri (lei of ii)clicatiiig the to the coloi-S slioi,ild be, Tll(@ coloi@@ iii F'10' iii ai.,e, blue on tbc@ 48 y " ' 7 elloav on the ti-ea, 49, and i-ed ori tli ai,(@,,t, 50, the 105 ea Lr @ 4:7, beiy)g left iiiitinted. A. ti,,.i,iispare-.ni, il-ai-Tiisl) tiiited t-,o the (,oloi, is u.-,e(I iii pi@-@ti@tice, @iiicl t,lie SC]-eell ])Iloto(@i-Lipliieally (@ithei- be tiiltecl oil it ()]" @,t ili-@iiispireiit screen -Li@,e(I is the ol),,ti-tictioiA 111) I)Podiieed I)Itotocyral)lii.calIN b(,ijio, tise(I oilly as a pattern. Coloiiiiig the sci-een loetill)r NN,itli ,t @fii-iiisli Nvlll eiitl)le t . li(@ screcii ilo 1)i,o(Iiice ii,,)oii tli(@ image pli,te locally i,ii effect -,iii,,ilo(yous to 11@) tli,,tt I)i@o(I-Liced by tlie ordiii@,11'y C()Iol. - Scilee7l. It ivill iiot, of coiirse, pi-odile(@, iny CO]oi,jiig of ttie. iiiiage plite or tli(,, I)icttii@e, l@)llt -,Aill @icconttiate or lessen ii-ierell, the effeet of a pai-ticiilar coloi@ 6f ,t 1), iitictilit- 120 of the ol)lect oii @i coi,i@esl)oil(Iiiio, ire@). o-f the iiiiage plate. The 1,)i-ocess of cti@i-yiiio- 01-it iiii, ini,elite(I @is I coiisider best 1-i-,is been iiidi(,,ttecl ill part iii clescribiii(T tl-ie device itself qn(I T 125 Altill iio describe nly the pot-tion-, of the w 0 pi@ocess n6t fully set forth@ above,. The seiisiti7edobstruction screen is placed ii-i the sliaclei@ aiid placed in the ea ert @,s sh6ANn ill I-II Fiu. I in the bellonvs 2 at the distiiiee re130