Full opinion text
MEMORANDUM OF DECISION ZOBEL, District Judge. Polaroid Corporation, the assignee of numerous patents in the field of instant photography, brought this action against Eastman Kodak Company for infringement of twelve of its patents relating to the art/technology of both film and camera. Kodak denied infringement and alleged that all of the patents are invalid or unenforceable or both. One of the film patents, U.S. Patent No. 3,761,269, this Court, on Kodak’s motion for summary judgment, held invalid as obvious within the meaning of 35 U.S.C. § 103. The parties waived their claims of infringement and invalidity with respect to a second patent, U.S. Patent No. 3,757,657, alleged to have been infringed by certain features of Kodak’s EK-4 camera. Trial proceeded with respect to the remaining ten patents on the issues of liability and infringement, on one hand, and invalidity and/or unenforceability on the other. This memorandum shall constitute my findings of fact and conclusions of law as to those issues. I. Background. In conventional photography, as opposed to instant photography, a picture begins as a sheet of plastic or paper coated with a thin layer of gel which has in it a suspension of microscopic crystals of silver halide. When that coating is exposed through the lens of the camera, the silver halide grains are modified to form an invisible image— the latent image. Exactly how the latent image is formed is apparently still subject to debate, but it involves the transformation of the silver halide into concentrations of minute, reduced silver particles depending upon the intensity of light on various portions of the film. To make the latent image visible, the film is placed into a developer — a reducing agent. The developer delivers electrons to the concentration of silver halide grains that form the latent image and further transforms them into metallic silver. Because the developer will continue to deliver electrons to the silver halide; ultimately reducing all to silver, the process must be stopped after a period of time when the latent image has become optimally visible. This is accomplished by briefly immersing the film in a dilutable acid bath. Because exposure of the film to light would wipe out the latent image, developing must be accomplished in a dark room. Following development, the film is put into a solvent for silver halide — hypo— which converts the remaining silver halide crystals into soluble silver salts and removes them by dissolving them. Since all of these chemicals would in time adversely affect the quality of the image, the film finally is thoroughly washed in water and dried, leaving a permanent negative image. The negative image is formed where light converted the silver halide into metallic silver, which is seen as black. The more light reaches a particular area, the denser the concentration of silver and the darker the image in that area. The brightnesses on the negative are thus totally reversed. To produce a positive, the process just described is repeated. The negative is projected onto sensitive paper carrying a silver halide emulsion either through an enlarger or by pressing the negative directly against the positive. The positive is then processed in essentially the same manner as was the original film. Edwin H. Land, the founder of Polaroid and the inventor of numerous patents, including several of those in suit, began work on what he came to call “one-step photography” in 1944. In 1947, he first introduced his version of the diffusion-transfer process by which the negative and positive were produced simultaneously. The film which will become the negative was exposed in the same manner as in conventional photography. The steps thereafter differed radically from those described above. The negative is brought into juxtaposition with a positive sheet within the camera and a viscous reagent contained in a sealed pod on one of the sheets is spread between them by means of two rollers. The positive and negative, which are symmetrical, are developed at the same time. After a defined period of time, the sandwich, positive and negative with reagent in-between, is pulled out of the camera and peeled apart. The camera also serves as the darkroom. Later, in the SX-70 system, the sandwich itself becomes the dark room. One-step photography, as first marketed in December 1948, produced a sepia colored photograph. That was replaced by black and white peel-apart film in the early 1950s. At the same time that these sepia and black and white films and cameras were being developed and improved, Land and his associates addressed the problem of instant color photography. Color photography requires three negative layers, each sensitive to a different primary color — blue, green or red. Complimentary dye layers — yellow, magenta and cyan, the subtractive colors positioned between the sensitive layers — absorb the primary color to be recorded on each sensitive layer. Thus, the blue sensitive layer controls the yellow dye layer next to it, which absorbs blue light; magenta absorbs green; and cyan, red. The dye layers are therefore sometimes called minus blue, minus green, and minus red. In conventional color photography, each sensitive layer contains a “coupler” and the dye layer a “color developer” which, by a reduction-oxidation process, will join together and form a dye. After exposure, the color developer is oxidized — it gives up electrons to the sensitive layer where the latter has been catalyzed by light. The silver halide layer is reduced — it gains electrons, enabling the col- or developer and silver halide to join. Each color uses a different coupler and the coupling process takes place within each layer. There is no transfer to different layers. Moreover, the reaction time of each coupler is different. Instant photography relies on a diffusion transfer process in which the reagents that form the negative image at the same time operate to form the positive. Coupler chemistry did not easily adapt to diffusion transfer. At Dr. Land’s direction, Howard G. Rogers, starting in 1947, began work on the problem of instant color film. The solution he evolved discarded couplers and relied instead on dye developers, a combination of preformed dye and developer, and led eventually to one of the patents in suit, U.S. Patent No. 3,245,789. By 1957, Polaroid had made a prototype of the first one-step color photograph, and in 1963 it introduced instant color to the market under the name Polacolor, a peel-apart product. Further work on both film and camera led to the introduction of the SX-70 system in 1972, described by Dr. Land as “absolute one-step photography.” It is an elegant, highly sophisticated camera and film system. The photographic unit, which is ejected from the camera immediately after exposure, develops into a visible image in daylight and requires no peeling. The camera designed for the particular needs of this film unit contains a motor, gear train, and pick which, working together, operate to eject the film unit. The photographer needs to do nothing but focus the camera and expose the film to obtain a finished print. Except for the ’789 dye developer patent mentioned above and the 165/262 opacifying layer patents to Rogers, all of the patents in suit pertain to innovations incorporated into the SX-70 system. From the early 1950s, Kodak had supplied Polaroid’s needs for negative material. After Polaroid’s development of the one-step color photograph, the parties, in December 1957, entered into an agreement pursuant to which Polaroid disclosed to Kodak certain of its color technology, including Rogers’ concept of dye developers, and Kodak cooperated with Polaroid to develop and produce negative material adapted to this technology. Kodak then continued to supply Polaroid’s requirements for negative material and the parties periodically met to discuss their research activities. About 1963, the research meetings terminated, although Polaroid continued to work on refinements and improvements in color and continued to inform Kodak of its progress from time to time. In April 1968, Polaroid advised Kodak of a radically new film, which would ultimately become the SX-70, and in October of that year, Dr. Land showed Henry C. Yutzy, Kodak's vice president of research, photographs made with the new method. The parties discussed a licensing and continuing supply arrangement, without coming to any resolution. In April 1969, Kodak notified Polaroid of its intention to terminate the 1957 agreement. , In early 1969, Kodak also launched its project PL-976 — an effort to put an instant product on the market by 1976. The object was to produce a high quality color print in the camera which preferably would not require peeling and to do so without the assistance of existing patents. PL-976, then optimistically redesignated PL-974 (moving back to 1974 the projected market date) investigated a variety of photographic chemistries. During 1970, groups at Kodak outside the research laboratory became more interested and the project was once again renamed and restructured. Project P-129 was begun to develop an instant color film similar to Polacolor and compatible with Polaroid cameras. P-130 was to produce an integrated system — Kodak film for a Kodak camera. The former, P-129, was abandoned toward the end of 1972 after an expenditure of 94 million dollars. Although the stated reason was that Kodak had been unable to solve certain problems caused by the particular chemistry used, the cessation of work on P-129 followed shortly upon the introduction by Polaroid of its SX-70. Contemporaneous Kodak memoranda recognized that any product created by P-129 would be obsolete even if it appeared on schedule. The P-130 effort continued with increasing intensity. Because Kodak sought to attain its objectives — camera and film— simultaneously, not sequentially, the expenditures of manpower and money were enormous. Between 1,300 and 1,400 people were assigned to P-130 at the peak period — late 1973 to mid-1975. Dr. Albert Sieg, Director of Photographic Strategic Planning, described the approach taken by Kodak. The different groups assigned to solve various discrete problems were to explore the existing technology and pursue parallel work on different applicable technologies. When no technology existed to solve a particular problem, invention was called for. That, in turn, required increased funding and increased resources. Despite these efforts, numerous problems defied solution. By the early part of 1972, Kodak had developed the “Lanyard” camera model, so called because the picture was to be ejected by use of a lanyard. It advanced the film by means of front picks. It did not contain a motor nor a gear train but did include devices to strip the pod from the photograph and to trim its edges. Although, as a consequence, the camera was relatively large, Kodak’s marketing people were content with its size. Following Polaroid’s SX-70 announcement in April 1972, and review by the P-130 committee of its implications, the committee found that the “P-130 program as earlier defined, was no longer desirable.” The Lanyard camera was too large by comparison to that marketed by Polaroid. Kodak also encountered numerous difficulties in its attempt to develop the film. Like Polaroid, it had to work out the imaging chemistry of integral film. By the fall of 1971 Kodak researchers had focussed on two dye release chemistries but did not achieve sufficient speed with either one of them until late 1972. By mid-April 1972, Kodak researchers had still not worked out a solution to the problem of dye stability and they had yet to solve problems associated with the mordant and the opacification layers. Although they hoped to achieve a “no-inventions” prototype by January 1973, a host of difficulties remained as late as mid-December 1972. It is undisputed that Kodak purchased large quantities of SX-70 cameras and film in October 1972, after they became commercially available. It is also undisputed that the several groups and departments involved in P-130 were ordered to familiarize themselves with the Polaroid product and to test it. As a result, Kodak’s marketing coordinators and managers commented in January 1973 that the P-130 program, as it then existed, was only “marginally acceptable.” They recognized that Polaroid had set the standard Kodak would have to meet and that even a “me-too” program would require more than two and one-half years to produce a less than equal design. Kodak did, in fact, introduce an integral system consisting of its EK-4 and EK-6 cameras and PR-10 film in April 1976. It is those products which, in several particulars, are alleged to infringe the patents in suit. Although, as Kodak correctly points out, this case involves nine different patent disputes and instant photography is not the perpetual domain of Polaroid, the response of Kodak to the SX-70 system has some bearing on the judgment concerning the underlying patents. Also while it is by no means decisive on the question of infringement of any particular patent, so does the suggestion in September 1973 of Kodak’s Development Committee that “[development should not be constrained by what an individual feels is potential patent infringement.” Kodak denies each allegation of infringement and argues the invalidity of each claim asserted against it. I will deal with the specific allegations of infringement and validity in the discussion pertaining to each patent. Certain broad contentions recur, however, and are properly addressed here. The parties are in substantial agreement on the standards for judging anticipation and obviousness under 35 U.S.C. §§ 102 and 103. They disagree in one area that bears on several of the patents in suit — the effect of Polaroid’s internal work and whether it constitutes part of the prior art against which the validity of a particular patent is to be judged. Work done within Polaroid which was not published is not prior art and I have not considered it in judging the validity of any patent. Del Mar Engineering Laboratories v. United States, 524 F.2d 1178, 1182, 207 Ct.Cl. 815 (1975). As to each patent, Polaroid relies on the presumption of validity. Kodak claims that this presumption is in nearly every instance undercut by Polaroid’s failure to disclose pertinent prior art to the Examiner. The parties have genuine disagreements as to what constitutes prior art, but I rule that Polaroid has fulfilled its obligation to the Patent Office where the patent in suit is in the class of patents that was cited. See, e.g., E.I. Du Pont de Nemours v. Berkley & Co., Inc., 620 F.2d 1247, 1267 (8th Cir.1980); International Telephone & Telegraph v. Raychem Corp., 188 U.S.P.Q. 214, 219 (D.Mass.1975), aff'd, 538 F.2d 453 (1st Cir.), cert. denied, 429 U.S. 886, 97 S.Ct. 238, 50 L.Ed.2d 167 (1976). In addition, prior art described in the specifications is expected to be considered by the Examiner. Gould v. General Photonics Corp., 534 F.Supp. 399, 403 (N.D.Cal.1982). Patent Examiners are also presumed to be aware of patents which issued from applications they had earlier examined. Hahn & Clay v. A.O. Smith Corp., 320 F.2d 166, 172 n. 15 (5th Cir.), cert. denied, 375 U.S. 944, 84 S.Ct. 351, 11 L.Ed.2d 274 (1963). In support of its argument that the patents are valid, Polaroid points to the commercial success of the processor product disclosed. The SX-70 camera and film system has unquestionably been immensely successful, as has Kodak’s product. The evidence presented is, however, inadequate to permit me to assign to any one patent credit for the commercial success of the whole. Accordingly, this factor has played no part in the decision. Finally, I have for the sake of completeness proceeded to consider the issue of infringement even as to those claims found to be invalid. II. U.S. Patent No. 3,362,821 Land U.S. Patent No. 3,362,821 concerns stabilization in one-step color photography. All photographic processes, as described earlier, implicate three steps — exposure (formation of the latent image), development (formation of a visible image), and stabilization (cessation of chemical reactions and preservation of the visible image). In conventional photography stabilization is accomplished by subjecting the film to different chemical solutions seriatim. One-step photography, by definition, required telescoping all of the steps, which is not to say that numerous steps did not occur sequentially within film and camera. Thus, chemicals were needed which would, when combined with the processing composition, permit development, then stop it at the optimal point and thereafter remain neutral. Solution of this problem was complicated by the fact that each type of film, sepia, black and white, and color, unexpectedly called for markedly different stabilization techniques. Polaroid’s first one-step film, introduced in 1948, produced sepia prints in a peel-apart format. For stabilization, Dr. Land used metal salts and water soluble esters. In the presence of the processing composition, the metal salts reacted with the esters to reduce the pH. Because their reaction rate with the alkali of the processing composition was relatively slow, they permitted formation of the image before they broke up to produce alcohol and neutralizing acid. Finally, the reaction of the several components of this system reduced the pH to an ideal level, just above neutral. Too much acidity would cause production of sulfur which, in turn, would attack silver and ultimately destroy the photograph. This stabilization mechanism was highly successful also because the photographer needed to do nothing but take the picture. Brown pictures were not ideal, however, and there was great pressure to produce black and white film. Because both sepia and black and white film involved silver transfer, Dr. Land and his associates had thought that the same stabilization process would work with black and white film. They found that it did not. To obtain a black and white print, the aggregation of silver ions was changed. That produced a shield. As a consequence, the metal salt, lead acetate, could not uniformly penetrate the black and white surface and the migration of the esters was also retarded. The ultimate solution was the print coater. The photographer had to swab each positive with a solution of a polymer and acetic acid that both washed the film and gave it a protective coating. This stabilizing system also required redesign of the black and white image and the support. Color film called for still different techniques. The timing needs of color were different from those of both sepia and black and white. During the 1950s and into the early 1960s, when Polaroid and Kodak still cooperated, scientists from both camps discussed a number of proposals, including a suggestion of Kodak’s Dr. Vittum to use an acid layer of commercially available sulfostearic acid. None worked successfully and as the scheduled date for marketing the new color film, Polacolor, approached, Polaroid expected to offer the film with a print coater. Even that, however, presented difficulties. Because the problems inherent in stabilizing color film differ radically from those pertaining to black and white, the coaters used different materials and required different “skills” from the user. The color print had to be coated within five seconds after removal from the camera. It had to be swabbed 16-18 times and the coating was slow to dry. The print coater was not only cumbersome and difficult to use, it also lacked elegance. During the summer of 1962, Dr. Land and his associates engaged in intensive investigation of alternative stabilizing techniques. To succeed, the stabilizing system had to meet three requirements. It had to allow the processing emulsion to retain its alkaline characteristics long enough to permit adequate image development and dye transfer. It then had to drop the pH abruptly and permanently to prevent further development and dye transfer, and third, it had to remove from the image-receiving layer the alkali metal ions introduced by the processing emulsion. The alkali metal ions, if not removed, would precipitate as salts in the image receiving layer and in time cause the image to become dull. In September 1962, Land conceived and indeed suggested to Messrs. Yutzy and Damschroder of Kodak, the use of a nondiffusible polymeric acid and associated timing layer. Unlike the esters which first had to decompose to provide a neutralizing acid, the acid polymer would react instantly upon contact with the alkali. The acid polymer would then abruptly drop the pH in the film structure by removing alkali metal ior.s from the processing solution and attaching them to itself. The layer had to be thick enough to provide adequate polymeric acid to accomplish the task, and a mechanism had to be incorporated to delay the reaction until the completion of development. The idea had two additional advantages. The polymeric acid, by removing the alkali metal ions, prevents the precipitation of metal and attendant dullness of picture. It thus produces more brilliant images. Color diffusion transfer by its very nature requires the disposition of a larger volume of alkali than does sepia or black and white film. The polymeric acid layer disposes of that alkaline environment and thus enables maintenance of a good image indefinitely. Polaroid immediately incorporated the concept of a nondiffusible polymeric acid layer into its Polacolor film which was, with that stabilization mechanism, introduced to the market in 1963. Dr. Land considered building the polymeric acid layer described above into two possible locations of the film unit: between the support and the adjacent image-receiving layer; or beyond the far part of the negative, that is, between the support associated with the negative and the innermost layer of dye developer. Two patents issued on this invention, one pertaining to the location of the acid layer near the positive, Land U.S. Patent No. 3,362,819; the other pertaining to an acid layer near the negative, Land U.S. Patent No. 3,362,821, the patent in suit. Polacolor employs the location described in the ’819 patent. Polaroid alleges that Kodak’s PR-10 film, which admittedly contains an acid layer, places the layer in the photosensitive element thereby infringing the ’821 patent. The ’821 patent discloses a layer of a nondiffusible acid-reacting reagent in the photosensitive element. It describes the preferred embodiment of the invention as a layer containing an acid-reacting polymer, and particularly, a polymer-containing free carboxyl group. The patent uses the shorthand expression — a polymeric acid layer. It includes a list of specific polymeric acids suitable to the purpose. The specifications teach that the polymeric acid layer is preferably 0.5 to 1.5 mils thick; that is, relatively thick as compared, for example, with the dye layers. The acid layer contains acid groups attached to a polymer so as to be nondiffusible. It reduces the pH in the image-receiving element by attracting alkali ions and then trapping them by precipitating them into the acid layer. The patent accordingly describes the acid layer as “a mordant for alkali.” It further teaches that the action of the polymeric acid must be controlled so that it will not interfere either with the development of the negative or with the image transfer of unoxidized dye developers. In other words, the reduction of pH must be properly timed. The patent suggests three timing mechanisms. A separate spacer layer of inert polymer may be used to delay contact between the alkali ions and their trap, or an inert poisoner may be mixed into the acid polymer to make the acid less accessible to the alkali ions. A third method calls for an acid layer with a relatively lower concentration of acid groups, again to prevent too rapid attraction and precipitation of alkali ions. The patent states that the polymeric acid layer “is provided in the photosensitive element and is positioned adjacent the support, i.e., between the innermost layer of dye developer and the support.” That positioning is depicted as well in Figure 1 of the patent. The specifications by reference to Figure 1 describe the photosensitive element as comprising “a support bearing, in turn, a layer containing as a nondiffusible acid-reacting reagent, a polymeric carboxylic acid ...” and the dye developer layers. The image-receiving element comprises a “support carrying an image-receiving layer.” Claim 1 is the only claim asserted against Kodak. In the context of color diffusion transfer processes, it claims the use of a layer of a nondiffusible polymeric acid containing sufficient acid groups to effect a reduction of at least two pH units in the surface of the image-receiving layer, compared with the initial pH of the processing composition, prior to the completion of the imbibition period. The acid layer is claimed to be contained in the photosensitive element and positioned between the support and the innermost negative layer. Kodak denies infringement and contends that the patent is, in any event, invalid under 35 U.S.C. §§ 102, 103 and 112 and that it is unenforceable. It relies in its post-trial brief on two prior art references listed in the Section 282 Notice: U.S. Patent No. 2,584,030 and Kodak French Patent No. 1,293,709. The ’709 patent is said to disclose the process described in claim 1 of ’821 and thus to render that claim invalid under 35 U.S.C. §§ 102(a) and 102(b). French Patent No. 1,293,709 describes color diffusion transfer processes employing coupler chemistry in which the photosensitive element is exposed, an alkaline-processing solution is applied, and a diffusible colored image is transferred to an image-receiving layer. It acknowledges that in “processes involving the transfer of dye images to mordanted reception layers, small amounts of alkali ...” may also be transferred and may be objectionable. One proposed solution is to wash the reception layer to remove such materials, and one method offered is “to squeegee the dye images into contact with a moist sheet containing ... an acrylic acid polymer ... to neutralize the alkali____” Alternatively, it suggests providing “a hydrophylic [sic] organic colloid layer containing the mentioned acids ... between the mordanted support and ...” reception layer, which layers are later stripped from the mordanted support. I find that ’709 does not anticipate claim 1 of '821. The acid layer in ’709 is not located in the photosensitive element, but between the photosensitive layer and its support. Both Dr. Land and Kodak’s expert, Dr. Trautweiler, agreed that the ’709 layer does not reduce the pH of the surface of the mordanted support, the analog of the image-receiving layer of ’821. More fundamentally, the acid layer of ’709 is a scavenging layer designed to prevent alkali from reaching the mordanted support, not a stabilizing system designed to stop the development process and prevent subsequent chemical reactions. The experts agreed, moreover, that they knew of no commercial unit in which dyes diffuse through an acid layer, that is, one in which the acid layer is positioned as in ’709. That patent does not describe the process of '821 and the process it does describe does not solve the problem addressed by '821. Kodak asserts that ’709, in any event, and U.S. Patent No. 2,584,030 disclose the technique of using an acid layer in the photosensitive element to reduce pH and that ’821 therefore represents no more than the application of routine skill. Kodak’s assertion is premised on a most narrow reading of the patent in suit, namely, that the purpose of the acid layer is to neutralize the processing composition and thereby to prevent stain caused by the oxidation of the developer. I do not, in view of the evidence adduced at trial, treat the invention so severely. The ’821 patent describes a system of stabilization that not only lowers the pH but does so in a specified manner with a timing mechanism. Its purpose is not merely to prevent stain but also to increase the light-stability of the dyes in the image. The specifications and examples teach the use of particular acids and acid layers of particular thicknesses. They teach three different timing mechanisms, which are earlier detailed, and the means of achieving light stability through trapping positive cations in the acid layer so that they cannot go to the image layer and damage it. For the reasons outlined earlier, I do not find in the '709 patent the teaching of the stabilization system of ’821, even to one of the high level of skill characteristic of those engaged in this field. The single reference on page 52 of a 53-page document to a “hydrophylic [sic] organic colloid layer containing ... acids” to remove “small amounts of alkali” from the mordanted reception layers does not teach the use of an acid layer with a timing mechanism. Nor does the peel-apart film of ’709 teach the location of the acid layer “in the photosensitive element.” The second prior art reference relied on by Kodak is Land’s ’030 patent, issued ten years before ’821. It teaches stabilization techniques useful for sepia images and describes two processes, one using heavy metal salts and the other, an acid. One of the acids specified is cellulose acetate hydrogen phthalate, which is also a preferred polymeric acid in '821. The ’030 teaches the need to reduce the pH of the liquid composition to 7, 6 or lower, and while it is preferable that “the acidifying substance” be “included on or associated with the image-carrying layer ...” such is not essential and “it might, for example, be positioned between the photosensitive layer and the base carrying this photosensitive layer____” This patent, like ’709, describes a peel-apart film structure. The acid layer is available to the alkaline reagent directly so that neutralization occurs immediately. The amount of acid must be small enough not to interfere with silver development. During processing, the acid is slowly dissolved by the processing composition while simultaneously the pH of the processing composition is slowly lowered. I credit the testimony of Dr. Land that this mechanism does not teach the system embodied in ’821. To say, as did Dr. Trautweiler, that if one deletes the words “col- or” and “dye” from claim 1, one gets the process described by the ’030 patent does not take sufficient account of the essential differences between the processes for sepia and color. Color diffusion transfer requires more time than the simpler silver transfer of sepia, and color requires the removal of the alkali metal ions from the environment of the image entirely. Neither these unique requirements of color, nor the mechanisms disclosed in ’821 for meeting them are disclosed in ’030. The evidence is undisputed, moreover, that the art had been full of experiment for several years, but no one had perceived the particular conformation, position and qualities of the ’821 polymeric acid layer for stabilizing color diffusion transfer film units until Dr. Land did in 1962. He was the first despite the fact that the parties in this case include on their staffs, without doubt, the world’s preeminent experts in the field of instant photography. Kodak further argues that the ’821 patent is invalid because it does not teach how to make the claimed invention as required by 35 U.S.C. § 112. One of the requirements of claim 1 is that the polymeric acid layer contain sufficient acid groups to effect reduction in the pH of the surface of the image-receiving layer of at least 2 pH units compared with the initial pH of the processing composition. Kodak’s expert, Dr. Trautweiler, calculated the drop in pH in several examples cited in ’821. His computations show a substantially smaller reduction and Kodak argues therefrom that the patent does not teach how to make the claimed invention. The calculations are just that — they are not based on experimental data. Moreover, Dr. Trautweiler did not view the system as a whole. Other components effect some reduction of pH before the acid layer begins its work. But the acid layer completes the process and does thereby cause reduction of the pH on the surface of the image-receiving layer by at least two pH units. In this fashion, the invention works precisely as claimed. Finally, Kodak contends that the patent in suit is unenforceable because Polaroid’s attorney and Dr. Land allegedly misrepresented the content of ’030 to the examiner and failed to inform the Patent Office of the existence of the ’709 patent. To prevail in this defense Kodak must show that Dr. Land and his attorney made misrepresentations with knowledge of their falsity or in an atmosphere of gross negligence as to their truth. It must further show that any information withheld was material. Materiality means facts known to the applicant which but for nondisclosure would have prevented the patent from issuing or would have restricted the claims. Digital Equipment Corp. v. Diamond, 653 F.2d 701, 715 (1st Cir.1981) (citing Union Carbide Corp. v. Filtrol Corp., 170 U.S.P.Q. 482 (C.D.Cal.1971), aff'd, 179 U.S.P.Q. 209 (9th Cir.1973)). The First Circuit does point out that the questions of culpability and materiality are interrelated such that an intentional scheme to defraud may require a lesser showing of materiality; a negligent misstatement, a greater one. Digital Equipment Corp. v. Diamond, 653 F.2d at 716. The ’030 patent was unquestionably cited to the examiner. Given my finding above on the relevance of its contents to the invention of the patent in suit, I find that Dr. Land and his attorney did not in any way misrepresent its significance. French Patent No. ’709 was not cited at all, but I credit the testimony of the attorney, Mr. Mervis, that he was unaware of it until many years later. I find, therefore, that the ’821 patent is valid against all of the defenses raised by Kodak. The issue of infringement hinges on the definition of the location of the acid layer in Kodak’s PR-10 film. Specifically, the question is whether the acid layer is “in the photosensitive element.” The parties do not disagree that the PR-10 acid and timing layers are positioned between a support and the photosensitive silver halide and associated dye layers. But Kodak points out first that in the manufacture of PR-10 the acid layer is coated on one support, the negative layers on another support, and that they are manufactured as separate elements and then assembled into one film unit. Because the negative and acid layers are coated on different supports, it argues, the acid layer is not positioned “in the photosensitive element.” The difficulty with that argument is that claim 1 is admittedly a process, not a product claim, and in defining the process it describes the position of the acid layer in the photosensitive element precisely where it is located in PR-10, “between the support and the innermost layer containing ... dye image-forming substance.” The photosensitive element is described in the specifications as including, in order, a support, a polymeric acid layer, a spacer or timing layer, and the layers containing the silver halide emulsions and dye developer. Regardless of the manner of manufacture, the sequence of layers in PR-10 is that described in the patent, and during processing, PR-10 is comprised of the same layers depicted in Figure 1 of the patent and has the same structure described in claim 1. Conflicting definitions of “photosensitive element” in other Polaroid patents do not save PR-10 from the claim of infringement. The term clearly has various possible meanings, as is shown by Kodak’s recital of other references. ’821, however, provides its own clear definition. A patentee is entitled to choose his own terms and to insist on them so long as he is consistent and does not contravene any single established or accepted meaning. Mooney v. Brunswick Corp., 663 F.2d 724 (7th Cir.1981); Harrington Manufacturing Co. v. White, 475 F.2d 788, (5th Cir.), cert. denied, 414 U.S. 1040, 94 S.Ct. 542, 38 L.Ed.2d 331 (1973). For the reasons stated, Land U.S. Patent No. 3,362,821 is valid and infringed by Kodak’s PR-10 film. III. U.S. Patent No. 3,245,788 As noted earlier, Howard G. Rogers began in 1947 to explore the possibility of importing color into one-step photography. Conventional color photography relied on coupler chemistry to produce color. A col- or developer became oxidized, and as a result combined with a coupler compound to form a dye. Different couplers were needed to produce different colors and each had a different reaction rate, making this process unsuitable for diffusion transfer which required a synchronization of reactions that coupler chemistry simply did not permit. Rogers sought to solve that problem by his coupling dye process disclosed in U.S. Patent No. 3,087,817, a patent not directly involved in this litigation. It used preformed dyes with coupling groups attached. In that process, the oxidized color developer joined with the coupler and its attached dye and thereby controlled not the formation of dye but the transfer of the preformed dye to the positive layer. That is, when the processing composition is introduced, the color developer is oxidized where silver halide was exposed and, as described before, it then joins with the coupler. The junction of color developer and coupler forms an insoluble compound which remains in the negative layer and is ultimately discarded as the negative is peeled. Where silver halide was not exposed no oxidation-reduction and no coupling takes place; the coupler with dye attached remains soluble in the processing solution and can transfer to the positive layer. The coupling dye process eliminated the problems attendant on different reaction times as the same coupling groups could be used for all dyes. But all color developer compounds used in the coupling process, paraphenylenediamines, themselves presented other difficulties. They were unstable when stored in the negative and had a tendency to desensitize the silver halide emulsion; they sometimes stained the picture; they could cause dermatitis; and they gave relatively slow reaction time and film speeds. In the early 1950s, Mr. Rogers proposed an entirely new approach, the use of dye developers. A single molecule of such compounds contains both dye to form the image and developer to develop the latent image in exposed silver halide and to control diffusion. The idea was to change the solubility and therefore mobility of the dye through oxidation by the developing silver. Mr. Rogers, in fact, hypothesized two possibilities, a “positive” dye developer which as a consequence of oxidation would produce a less soluble product, and a “negative” dye developer which would create a more mobile dye product. These concepts were ultimately embodied in two patents, respectively, U.S. Patent No. 2,983,606 and No. 3,245,789, the patent in suit. The positive dye developer process disclosed in the ’606 patent is the one which Polaroid has used commercially in all of its color films since the introduction of Polacolor. Polaroid alleges that the negative dye developer process was incorporated into Kodak’s PR-10 film. The positive dye developer process works as follows. After exposure and the introduction of the processing compound, an auxiliary developer, which may be included in the processing compound or built into the negative layer, will in the exposed portions of silver halide, give its electrons to the silver halide. It, in turn, takes electrons from the dye developer, which thereby becomes oxidized. Oxidation precipitates the dye, thereby fixing it in the negative layer. Where silver halide was not exposed, the dye developer is not oxidized; the dye is not precipitated, and the dye therefore is able to transfer to the positive layer to form the colored image. In both the developed and undeveloped portions, the silver halide stays in the negative. Where the scene is light, the dye is held back in the negative by its precipitation there, while in the darker portions of the picture where silver halide remains undeveloped, and the dye developer unoxidized, the dye is free to move to the positive, the image-receiving layer. As described in Rogers U.S. Patent No. 3,245,789, issued to Polaroid Corporation on April 12, 1966, on Application Serial No. 107,889, filed on May 5, 1961, in the negative dye developer process the dye is transferred to the positive layer in the exposed — the developed — region of silver halide. In general terms, the dye developer, which has relatively low mobility to begin with, is, as is true for the positive dye developer process, oxidized. In the negative dye developer process, however, the dye developer splits off a dye molecule as a result of oxidation. This molecule then has a lower molecular weight and greater solubility, so it becomes more mobile. It is then able to transfer to the positive layer. Where silver halide is not exposed, the dye developer is not oxidized and not split. Being relatively immobile, the unoxidized dye developer remains in the negative. Specifically, the patent discloses a color diffusion transfer process for forming col- or photographs or transparencies using compounds referred to as “negative transferring developing agents.” If colored, these compounds are described as being dye developers in the reduced state, “i.e., they are compounds which are both dye and a silver halide developing agent.” They are characterized as being “relatively nontransferable to the image-receiving layer” but they form a substantially more mobile, diffusible oxidation product. That is, the colored oxidation product is more diffusible than the unoxidized negative transferring developing agent. The patent suggests that the photosensitive element of the film unit, the negative, contains in the silver halide emulsion a layer of the dye developer. When, after exposure, the liquid processing composition is introduced, it permeates the emulsion to provide a solution of dye developer. Then, as the exposed silver halide is developed, the oxidation-reduction reactions previously described and the attendant transfers of dye molecules take place. Polaroid charges infringement of claims 5 through 9. Claims 6 through 9 are dependent on claim 5. Claim 5 describes the process outlined above. Claim 6 adds the requirement that the mobile oxidation product be a dye that absorbs light in the same region of the spectrum in which its associated silver halide emulsion is sensitive. Claim 7 provides for positioning the dye developer layer between the silver halide emulsion and the film unit support. Claim 8 claims the addition of an auxiliary developing agent, which is colorless. Claim 9 adds the requirement that development be effected in the presence of an antifoggant. Kodak challenges the validity of the patent and denies infringement. It asserts, first, that the process taught in the patent and claimed in claim 5 does not in fact work, as required by 35 U.S.C. §§ 101 and 112. Second, it contends that the process is anticipated by the prior art and that it is, in view of the prior art, obvious. Resolution of these contentions depends on the date of invention and the scope and content of the prior art applicable in light of that invention date. Finally, Kodak argues that PR-10 practices the prior art and not the teaching of the patent in suit. Therefore, either the patent in suit is invalid in view of the prior art or, if valid, it is not infringed. Section 101 provides that “whoever invents ... any new and useful process ... may obtain a patent therefor.” Section 112 requires that the specification contain “a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art ... to make and use the same____” Kodak asserts first that the ’789 invention is useless because, as described, it will produce at best a poor image. This is so, it says, because the negative dye developer must be mobile even in the unoxidized state to serve as the developing agent for the silver halide. That is, unless the dye developer molecules are mobile, they cannot move into contact with the silver halide. Kodak asserts that if they are mobile, the developer molecules will transfer to the positive layer unoxidized and thus cause poor image discrimination. Second, Kodak argues that the patent, in fact, discloses only one negative dye developer compound, bis-sulfonyl hydrazide, and that this compound does not work even in a peel apart format which mechanically stops any further diffusion transfer. A fortiori, it does not work with integral film. The argument does not accord with the appropriate legal standard and it misconceives the disclosure of the patent. A patent is invalid under § 101 if the “invention is ‘incapable of achieving any of the aims of the patent under any conditions.’ ” E.I. DuPont de Nemours & Co. v. Berkley & Co., 620 F.2d 1247, 1258 n. 10 (8th Cir.1980). The process described in this patent does occur precisely as planned. Experiments by both parties demonstrated that the negative dye developer molecule split when oxidized and thereby produced a mobile dye which transferred to form an image that corresponded to developed areas in the negative. Although the evidence showed that the images obtained were poor, because more dye developer transferred than is desirable, I credit the testimony of Mr. Rogers that the solution, to add a larger ballast, was an expedient well known in the art. Indeed, Dr. Lee J. Fleckenstein, a senior research associate in the Color Instant Laboratory Division of Kodak, testified at length about the experiments he conducted, beginning in 1958, with various compounds and ballasting groups. I am persuaded therefore that one of ordinary skill in this field “would be able to understand the patent disclosure and, from that disclosure, using the skill of the art, could build an operative system.” Decca Ltd. v. United States, 544 F.2d 1070, 1077, 210 Ct.Cl. 546 (1976), cert. denied, 454 U.S. 819, 102 S.Ct. 99, 70 L.Ed.2d 89 (1981). Accordingly, the patent is not invalid under either § 101 or 112. The remaining issues of invalidity are bound up with the issue of infringement. They all require determination of the date of the invention of ’789 and the manner in which the processes described in the cited patents and patent applications and those of PR-10 and ’789 work. The background of the inventions disclosed in the ’606 positive dye developer and ’789 negative dye developer patent is outlined above. Mr. Rogers conceived of the idea of both positive and negative dye developers at some time during the early 1950s. He thereafter conducted experiments with positive dye developers and succeeded in obtaining image transfer by 1955. He did little, if any, work with negative dye developers because they were relatively slow and required the use of reversal emulsions. Mr. Rogers had, however, observed the effects of negative dye developers and he recalled that the images were poor and transient. In 1955, Polaroid very broadly disclosed both positive and negative dye developers in the form of an amendment, claim 28, to a pending patent application, Serial No. 415,-073. The claim was rejected by the Examiner and Polaroid eventually cancelled it without prejudice. Polaroid did not by this action concede invalidity of that claim. In 1957 Polaroid disclosed both positive and negative dye developer processes to Kodak pursuant to the mutual disclosure agreement made in December, 1957. That document states that “Polaroid has examined a large number of processes for obtaining transfer images in color,” and that except for a few described in the literature, these processes are described in patents and patent applications appended to the document. The descriptions refer to particular chemicals and the manner in which they react; the use of reversal emulsions, antifoggants and auxiliary developers; and a variety of arrangements of the several layers of a film unit. The document also asserts that “[Njegative transfer images may be obtained by forming a mobile dye as a result of development of the latent image____” It specifically discloses the use of “a sulfonyl hydrazide of one or two molecules of a dye,” the class of compounds used in Example 1 of the patent. The application for the ’789 patent was filed on May 5, 1961. Polaroid claims an invention date at least as early as 1953, but, in any event, no later than December 1957. To sustain either date, it must prove both that by that date Mr. Rogers had conceived of the negative dye developer and that he had reduced it to practice. That is, Polaroid must show not only that Mr. Rogers formulated the process in his mind, but also that the process had been successfully performed. To show reduction to practice it must show that “the series of steps constituting the process ... [have been] carried out in such a manner as to demonstrate the practicability of the process.” Bell Telephone Laboratories v. Hughes Aircraft Co., 422 F.Supp. 372, 380 (D.C.Del.1976) (quoting 1 Rivise and Caesar, Interference Law and Practice § 131 (1980)), aff'd, 564 F.2d 654 (3d Cir.1977), cert. denied, 435 U.S. 924, 98 S.Ct. 1489, 55 L.Ed.2d 518 (1978). Despite the disclosures in the 1955 patent application and the 1957 document to Kodak and despite the fact that the latter refers to the compounds ultimately specified in the patent, Polaroid adduced no evidence of any documented experiments that demonstrated the efficacy of negative dye developers until the experiments conducted in November 1960. Mr. Rogers’ testimony concerning his observations during the 1950s was tentative and constitutes tenuous evidence of reduction to practice at best. Accordingly, I find that ’789 is entitled to an invention date of November 1960. To show both invalidity and noninfringement, Kodak relies on the splittable coupler process represented by its British Patent No. 840,731 granted on July 6, 1960 and three references based on inventions of K.E. Whitmore and P.M. Mader of Kodak. The last three are also directed to the splittable coupler process; but they disclose in addition a “deamination” process. In the splittable coupler process of the British patent a mobile color developing agent develops the exposed silver halide and becomes oxidized. It then moves to a dye release compound composed of a preformed dye to which is attached a conventional color coupler (para-phenylenediamine) and ballast group. The oxidized developer displaces the dye molecule which is thereby split off. The dye thus becomes mobile and is able to transfer to the image receiver. It is a process that, all parties agree, takes place in two steps and is relatively slow. The deamination process of Whitmore-Mader also operates in two steps. It uses black and white, not color developer. However, the initial reaction is similar to that of the splittable coupler process. The developer reacts with exposed silver halide and becomes oxidized. It too moves to an immobile dye group but instead of simply displacing the dye molecule it first oxidizes the dye compound, thereby being itself reduced to its original state. The oxidized dye group, which is called a “quinoneimine,” undergoes another reaction. As the Australian specification puts it, “subsequent treatment with, for example, strong alkali causes deamination to take place and the splitting off of ...” a diffusible dye for transfer to the reception layer. The residue is still ballasted and therefore immobile; it remains behind. Because the split dye segment contains an “amino” group, the process is called “deamination.” In the PR-10 process, according to Kodak, black and white developer is oxidized by exposed silver halide. The oxidized developer moves to the adjacent layer of a ballasted immobile dye release compound, sulfonamidonaphthal, oxidizes it and becomes itself again reduced. The oxidized dye release compound, a quinoneimide, undergoes hydrolysis, resulting in its being cleaved into a mobile, diffusible dye and an immobile ballasted group. Because the split dye contains an amide group, Kodak calls the process “deamidation.” Kodak asserts that this is the process described in the prior art and that it is a process different in kind from that described in ’789; but if it were deemed to infringe ’789, then ’789 is both anticipated by and obvious in view of that prior art. Kodak’s first argument, that its PR-10 process is different from and does not infringe the process disclosed in ’789, has several elements. It asserts that in the ’789 process, the dye containing compound, the dye developer, is mobile and moves to the silver halide, whereas the corresponding compound of PR-10 does not. It further argues that in ’789 the dye compound develops silver halide; in PR-10 it does not. In ’789 oxidation of the dye compound causes a diffusible dye molecule to be split off; in PR-10 oxidation forms a new immobile compound with dye still attached. The dye splits off only upon the next reaction, hydrolysis. In ’789 the oxidation reaction is irreversible; in PR-10 the developer compound is oxidized by the silver halide but then returns to a reduced state after oxidizing the dye compound. Kodak’s analysis of the ’789 process is premised on a strained and narrow reading of the patent and it hinges on the terminology used in describing these two processes. If the terms are changed, the analysis fails. First, claim 5 of the patent does not require the dye containing compound and the developing agent to be one and the same. Therefore, it does not require that the dye-containing compound be mobile so as to contact the silver halide. See infra note 9. Claim 5 does not call for development by the negative dye developer; rather it states that silver halide is developed “in the presence of a negative dye developer.” (emphasis added). I credit the testimony of Mr. Rogers that the auxiliary developer is the agent that contacts and develops silver halide. It moves back and forth between the layers of dye developer and silver halide, oxidizing the former and reducing the latter. The fact that claim 8 of the ’789 patent specifically calls for the use of an auxiliary developer does not mean that claim 5 is not broad enough to include its use. See Application of Smythe, 480 F.2d 1376, 1381-82 (C.C.P.A.1973); United States v. Adams, 383 U.S. 39, 48-49, 86 S.Ct. 708, 712-13, 15 L.Ed.2d 572 (1966). Thus the patent does not require either explicitly or implicitly, that the dye developer be mobile before oxidation. Functionally, therefore, the negative dye developer of '789 corresponds to the dye release compound of PR-10, not to the developer or electron transfer agent of the latter. Second, Kodak’s argued distinction between the oxidation processes is as well more apparent than real. The oxidation and cleaving reactions of PR-10 and ’789 occur in a similar manner and with one treatment. The parties agree that oxidation of the negative dye developer of ’789 results in splitting off a diffusible dye molecule. The reaction takes place in the alkaline processing composition and it is without question a one-step reaction. ’789 does not describe a separate alkali step, but the alkali attack is an important part of the reaction. The oxidation and splitting reactions in PR-10 also take place in the alkaline solution and I find that they occur essentially simultaneously. That is, when oxidized, the dye compound cleaves into dye and immobile by-product virtually instantaneously. I credit the testimony of Mr. Rogers that the reaction mechanisms ’789 and PR-10 are the same. Although Kodak describes the PR-10 process in terms of successive oxidation and hydrolysis reactions, those, in fact, occur at the same time; in Mr. Rogers’ words, the reactions happen “in one fell swoop.” Finally, there is no difference between the two processes in the manner in which the developer (the electron transfer agent — the black and white developer of Kodak and the auxiliary developing agent of Polaroid) functions. In both, the developer is alternately oxidized by the exposed silver halide and reduced by the dye containing compound. Kodak unquestionably spent considerable time and effort to achieve a dye release process and I do not doubt the testimony of Dr. Fleckenstein concerning his experiments in 1969 with sulfonamidophenols and his observation of their reactions. The sulfonamidophenols are in reality, however, another species of negative dye developer. PR-10 in fact employs sulfonamidonaphthols but the parties agree that they are simply a stronger developer. They do not differ in reaction from the phenols. I find that those compounds follow the same reaction path as do the compounds of the ’789 patent. Kodak additionally argues, however, that if PR-10 and ’789 are construed to involve the same process, then the process disclosed in ’789 was anticipated by the prior art and therefore the patent is invalid. I find that both processes are fundamentally different from those described in the prior art. The Whitmore-Mader proposal requires after oxidation of the dye compound “subsequent treatment with ... strong alkali” which causes deamination and splitting off of the dye. In contrast, ’789 and PR-10 are one-step processes. The Whit-more-Mader process is, moreover, of questionable utility. The dye group specified is a para-phenylenediamine compound and therefore suffers all the disadvantages attendant on the use of that chemical. Mr. Rogers testified that the process has no commercial value for the additional reason that the compounds specified could give rise to extraneous competing reactions that would result in less mobile dyes and a reduced yield of diffusible dye. Kodak did not, in fact, pursue the deamination proposal in the succeeding continuation-in-part application which resulted in the grant of a patent. Whitmore-Mader does not anticipate ’789 nor are the teachings of '789 obvious in view of Whitmore-Mader. The PR-10 process infringes every element of the claims of the ’789 patent that Polaroid has asserted. It is a diffusion transfer process in which exposed silver halide is developed “in the presence of” a sulfonamidonaphthol dye releaser which is a colored silver halide developing agent. In PR-10, the dye releaser or developing agent is oxidized as a function of development and forms an oxidation product, the dye, which is more mobile in the alkaline solution than was the dye releaser, and which transfers by diffusion to the image-receiving layer. It thus infringes claim 5. PR-10 also fits the added elements of claims 6 through 9. It employs the relationship between dye color and silver halide sensitivity specified in claim 6. The dye releaser of PR-10 is positioned in the photosensitive element in a layer between the silver halide and the support, as required by claim 7. The electron transfer agent of PR-10 is the colorless “additional silver halide developing agent” of claim 8 and development is effected in the presence of an antifoggant as required by claim 9. Because ’789 does not practice the teaching of Whitmore-Mader, it is neither anticipated by nor obvious in view of those prior art proposals. Because PR-10 does practice the teaching of '789 it infringes the asserted claims of that patent. IV. U.S. Patent Nos. 3,594,165 and 3,689,262 The development of a photograph must occur in a darkroom because exposure of the latent image to light will destroy it. The conventional darkroom has no place in instant photography, however, so Polaroid evolved several means of shielding t