[1]Patented June 17, 1941 2 1 2 4 6 , 0 1 3 .UNITED STATES PATENT OFFICE 2,246,013 COLOR SOUND FHM Karl Schinzel, Rochester, N. Y., and Ludwig Schinzel, Troppau, Sflesia; said Karl Schinzel assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application June 18, 1938, Serial No. 214,578 In Austria June 25, 1931 2 Claims. (OL 95-2) This invention relates to pho tographic color taking of the scenes, and the sound irecord exfilms having sound images therein, and to methods of producing such fflms. Development of a sound film to a certain gamma is only a poor compronuse. It would be 5 ideal, if the sound track and the image could be developed entirely independent of each other. in the accompanying dr@Lwing, the figure is a flow diagram showing sectional views of successive steps in one method of formiri-- a sound 10 track image according to our invention. On thin single emulsions drying vel@y rapidly, this may be realized by developing first only the scenes or the sound tracli to the desired density, using anti-fogging agents, for example, nitro- 15 benzimidazole and other azimides, tri- and tetrazoles, thiosemicarbazones. The film is then dried and the bther image printed, developed, etc. Variable width recording sho@ld be printed and developed before the sdenes. Very thin and 20 weakly tanned emulsions do not have to be dried, . and the next image may be printed immediately after development and washing of the first image. Addition of anti-fogging agents is necessary in the second development. 25 Double emu,sions or those having differently sensitized zones are superior, the' scenes being in one emulsion layer or zone and the sound track in thd other one, nearest th'e support. Thin emulsion layers must be used to shorten the dry- 30 ing ta'me. The emulsion for the. variable width recording may be much thinner and harder than that for the geenes,. wb.ich should be s6fter and perhaps more @ sensitive or contain more silver halide. The two emulsion layers are sel)arated 35 from each other by an easily decolorized yellow filter layer and printed from different @ides. The color sensitivity of the emulsion layers may als6 be different, one for blue-green or yellow, and the other for red or infrared, and they are 40 printed witb the cotresponding light. Ultraviolet light should be used for printing the variable width record on a fine-grain or grainless emulsion. A yellow or colorless ultraviolet-absorbing intermediate layer, must then be present and 45 the original sound record milst be on maierial which is opaque to ultraviolet rays, for example, on copper ferrocyanide. X-rays may also be used for printing, if the silver halide of the sound track emulsion has been sensitize d with the 50 thorium salt of eosin, and the ori@inal is transparer b to X-rays. The variable width sound recposed or printed simultaneously or later on the negative for which also ultraviolet rays or a cathode ray oscillograph may be used. The lower emulsion may be tanned or consist of hardened gelatin, and the upper emul@ion of soft gelatin. After the image in the upper emulsion is developed and fixed, the sound track In the lower emulsion layer is developed for a longer time and in 9, slightly v@,armed developer or after destruction of the tanning effect. This lower emulsion layer may also consi@t of silver halide collodion emulsion which may have been hardened before coating the upper emulsion layer to make it moredifficultly developable. Both emulsion iayers,must, of course, be differently sensitized, or separated from each other by a filter layer, or -even dyed, and they are printed from both -ides. A light-sensitive sub.,.;tance, which 'is not attacked by the developer required for the other emulsion layer, is used for the sound track. The lower emulsion layer, consisting of gelatin, collodion, etc., may also contain leuco bases, insoluble or at least not noticeably diffusing salts of indigosols, thioindigosols or similar leuco esters, also black or any other coiored or colorless substances which do not react during development of the -tipper emulsion layer containing the imag6, And are also ianaffected by hypo, as for example, onitrobenzaidehyde, diazo 'sulfonle acids and diazo anhydrides with or without the necessary co-ndonents. The sound track Is now printed to the desired dens - ity frdm Che o'n'ginal or its. copy which must be'opaque to uitraviolet, using the strong ultraviolet rays of a mercury quartz lamp. Mnally, the unused bases are washed out in dilute ihonochioracetic acid, salts of @indigosols with einchonine, triphenylguanidine, guan-@ idine, etc., in@dilute solutions of sodium carbonate, ammonia or sodium hydroxide wh may have to be l@repared with alcohol. Unused anhydride Is coupled to ltseif or to the component in ammoiiia vapors, dilute alcoholic sodium hydroxide, or animonia; or @apors or solutions of acetone and ammonizi are ailowed to react on the residual o-nitrobpnzaldehyde. The lightsensitive substance for the sound track may also consist of mercur!4@. bromide or other organic salts, and the residue may be blackened after development and fixing with sodium sulfide. Emulsions of slight sensitivity pf the Lippmann ord should be printed and developed before,the , type which may be sensitized may also be physscenes. If the emulsion for, the scenes is suffi- ically developed by the Goldberg or Odell methciently sensitive,. it may also be used for direct 55 ods, but the sound track must be printed corre-
[2]2 2,246,013 spondingly longer. Although the scenes developed previously are intensified by this procedure, this effect may be lessened without harm to the fflm by wiping the fUm off after protecting the sound track. Two different suver halide emulsions are used In which the silver halide of one emulsion layer Is more easily developed than that of the othel layer. Among the possible combinations are AgCI-Ag]3r, AgCI-Agl, Ag]3r-AgI. The first one appears to -be the best adapted, since silver cmoride is much more easily reducecl by certain developers than silver bromide. For printing, ho-wever, mercuric brornide, silver Iodide, and especially silver ferrocyanide, are better. suited, because they are much less attacked than silver ferrocyanide, but they cannot, or only to a limited degree, be made color sensitive. If a lower silver Iodide emulsion layer is combined with a soft upper silver bromide emulsion.sensitized with erythrosine,- and both are separated from each other by an easily decolorized yellow futer or are ten-iporarily colored yellow, the scenes are developed first In the upper emulsion layer with a weakdeveloper, the residual silver bromide immediately fixed out, and then the sound track developed in the lower silver iodide emwsion with a strong developer and fixed. A lt7o sodium quinone sulfonate solution and 5% anbydrous sodium sulfite (hydroquinonedistilfo.-Ac acid) develops an Image on suver chloride gelatin In a few minutes, but it does not affect overexposed silver bromide after half an hour's de'velopment. Hydroquinone, pyrocatechin, p@,rog@-Ilol, amidol, and numerous other developing substances behave similarly under certain conditions which are described In detail In the litergture also several simple and compound color developers (Schinzel patent P-pplication S. N. 139,758). TWs difference of developability is less s-briking in silver chloro-bromide emulsions. If tne original triple-emulsion, however, consis'@s of silver chloride, a four'th lower silver bronlide emulsion may be arranged -for the sound track. A fllm of this type is iilustrated in.the first stage of the figure of the accompa@nying drawing in. which 10 is a suitable transparent support coated wlth a silver halide layer II of soft gela@tin ior recording the sound track, and silver halide layers 13; 14 and (5 sensitive re-' spectively to the'red, green and blue regions of the spectrum and consisting of hard gelatin, all of these layers being separated fkom the soft gelaiin layer I I by a yellow or ultra-violet futer layer 12. The picture area of the fllm is exposed from the emulsion side to form latent Images In the hard gelatin -layers and since the film contains the fllter layer 12 these images are not recorded on the layer I I which is sensitive only to blue light. After exposing or printing of the three separation images on the silver chloride gelatin emulsions, the exposed picture areas may then be developed, as shown in the second stage of the flgure to form images 16, 17 and 18 In the layers 13, 14 and 15, respectively, the sound track alone being printed dry and through the back on the correspondingly sensitized silver bromide emulsion or on one i@rotected by futers. This emulsion layer Is sensitized for Infrared or SeParated from the triple-emulsion by an ultraviolet-absorbing Mter, according to whether Infrared or ultraviolet-light'is, used for printing. If the picture areas have not been already deveinone sulfonic acid and sodium sulfite oa the places of the residual silver chloride, coupled with the components In the three-emidsion layers by means of Pamainodimethyl-aniline, and the sound track developed simultaneously, or If the picture areas have already been developed the expdsed soft gelatin layer I I may be developed to form a metallic silver sound Image 19, then all reduced silver converted Into silver ferrocy10 anide. the residual suver bron-dde developed and finally fixed. This leaves dye images 16, 17, and I 8 in layers 13, 14, and 15 and sound image 19 In layer I 1, as shown in the tliird stage of the flgure. In a variation, one may develop the 15 residual silver bromide to.any dye and remove all silver simultaneously with Farmer's reducer. It is, of course, understogd that in all materials mentioned in this description anti-halation layers must be used, so that very sharp sound 2o records and prints may be obtained. It Is sometimes of advantage to combine some of the methods described with "controlled diffusion." The action may be limited to the outer most layer or zone, if alcoholic solutions of de25 Velopers or other reagents containing only a few per cents of water are used, so that an independent developrnent of the sound record Isguaranteed. Oxidizing agents may also be used in this form for the reduced silver of both emulsions, 3o and oxidize only the silver in the upper emuision, or convert it Into other compounds which may later be dissolved by water gr hypo. It Is, of clourse, assumed that the emulsion intended for the sound track Is on top, If such a treatment is 35 considered; in this case, It may be necessary to expose through the back. In the examples given in the present description of prlnting tliree-color Images with or without sound track, as well as in analogous printing 40 processes with colored development and coupling, it is often desirable to reproduce black as a color, or as silver instead of thesubtractive method of superposition of - three dyes, if necessary, for the separation image. This black separation image 45 can be produced relatively simply by processes based on colored development and coupling, where the entire silver Is stiII present pt the end in the tripie or single emulsion. It Is only necessary to rehalogenate or to sensitize. The black ri, 0 silver is developed and fixed or- converted to a black dye, an d the -silver thoroughly removed with Parmer's solution. In the oxidation methods mentioned in this description, the matter Is simple orily when siiver salts or metallic silver r)5. is still present which may easily be converted into sensitive sflver halide or perhaps suver ferrocyanide, after which the procedure is the same as Just outlined. Otherwise, one is obhged to obtain an insoluble silver halide or silver ferro60 cyanide by conversion with a silver salt solution, or to Impregnate with light-sensitive salts, or to precipitate a silver halide diffusely through the entire emulsion and to obtain the black image by exposure and development, also colored develop65 ment, and fixing. What we
