Full opinion text
DECISION and ORDER MICHAEL A. TELESCA, District Judge. By Order dated September 26, 2006, upon consent of the parties, I appointed Special Master Joseph W. Berenato, III, as a Special Trial Master in this matter for the purpose of conducting a bench trial and issuing a Report and Recommendation to the court as to how the issues of liability in this case should be resolved. From May 3 to May 11, 2007, Special Master Berenato conducted the bench trial of this matter, and on September 7, 2007, he issued a thorough, well-reasoned 122 page Report and Recommendation recommending that the court find: (1) that the defendants’ products Cronex 10TL and Orthovision G infringe plaintiffs U.S. Patents Nos. 4,425,425, 4,425,426, and 4,439,520; (2) that the remaining accused products do not infringe plaintiffs patents; (3) that the asserted claims of the plaintiffs patents are valid; (4) that the asserted claims of the plaintiffs patents are enforceable; (5) that the defendants’ infringement of plaintiffs patents was not willful, and (6) that plaintiff failed to provide defendant with notice of infringement with respect to Cro-nex 10TL prior to expiration of the patents in suit, and therefore, plaintiff is not entitled to damages for the infringement of those patents with respect to Cronex 10TL. On September 27, 2007, and October 2, 2007, respectively, Special Master Berena-to issued two additional Reports with respect to evidentiary issues and trial matters. Thereafter, in accordance with the court’s September 26, 2006 Order, the parties filed objections to the Special Master’s Reports. Following a review of the record de novo, for the reasons set forth in Special Master Berenato’s September 7, 2007 Report and Recommendation, I adopt that Report and Recommendation in its entirety without modification. As an initial matter, I find no legal error in any aspect of the Special Master’s Report and Recommendation. The authority relied on by the Special Master is appropriate and controlling, and I find no error in the Special Master’s legal analysis or conclusions. With respect to the Special Master’s development and discussion of the factual record in this matter, his analysis of the facts is so comprehensive and so complete, additional discussion of the factual issues would serve no fruitful purpose. In short, Special Master Berenato provided the court and the parties with an extensive and detailed explanation as to how and why he arrived at his recommendations. Because I agree in whole with his Report and Recommendation, I adopt his September 7, 2007 Report and Recommendation in its entirety, and make it a Final Order of this Court. With respect to the parties’ objections, I find that the issues raised in their objections were thoroughly explained by Special Master Berenato in his Report and Recommendation, and accordingly, I deny those objections without further comment. Finally, for the reasons stated in the Special Master’s September 27, 2007 and October 2, 2007 Reports, I adopt those Reports in their entirety. ALL OF THE ABOVE IS SO ORDERED. REPORT AND RECOMMENDATION JOSEPH W. BERENATO, III, Special Master. INTRODUCTION Pursuant to the Court’s Order of September 26, 2006, the undersigned was appointed Special Master to issue a Report and Recommendation on the construction of the claims and, upon agreement of the parties, to issue a Report and Recommendation on the liability issues. The Report and Recommendation for Construction of Group I Patents was filed March 21, 2007. Trial was held May 3-11, 2007. Thereafter, the parties filed post-trial findings of fact and conclusions of law. The parties also submitted a list of exhibits as to which they agreed there were no objections to admissibility. Additionally, Defendants filed a post-trial motion seeking the admission of an exhibit to which Kodak had objected. A Report and Recommendation on that motion and the objected to exhibits is being separately filed. Having heard the witnesses and considered the parties submissions, the following constitutes my Report and Recommendation regarding the ultimate issues of liability- Background As originally filed, this case involved alleged infringement by Defendants Agfa-Gevaert N.V. and Agfa Corporation (collectively “Agfa”) of seven patents owned by Plaintiff Eastman Kodak Company (“Kodak”). By stipulation of the parties, the so-called cross-over patents were eliminated from the case and trial proceeded based upon the T-grain patents. The T-grain patents are U.S. Patents Nos. 4,425,-425 (“the '425 patent”), 4,439,520 (“the '520 patent”), and 4,425,426 (“the '426 patent”). The '425 and '520 patents expired November 12, 2001 and the '426 patent expired September 30, 2002. Moreover, the '426 patent was the subject of a patent reexamination, Reexamination Control No. 90/001,255, filed June 8, 1987, by E.I. du Pont de Nemours & Company (“DuPont”), predecessor in interest to Defendants. As a result of the reexamination, no claims were canceled or amended although Kodak submitted affidavits and remarks distinguishing certain prior art. Subsequent to the reexamination proceeding, DuPont spun-off its X-ray film business interests in 1996 as Sterling Diagnostic Imaging, Inc. (“Sterling”). In 1999, Agfa acquired Sterling and assumed Sterling’s patent infringement liabilities. Trial Tr. 669 (Verhoeven); TX 99 (Agfa Corp. Depo. Exh. 53 § 2.03). During its existence, Sterling manufactured X-ray film products at a plant in Brevard, North Carolina and sold such products in the United States. TX 823 (Response to Interrogatory No. 1 at 10), 28 (Agfa Corp. Depo. Exh. 48). Kodak contends that claims 1-3, 5-9, and 19 of the '425 patent are infringed, that claims 1-5, 8-10, 13, 16, 19, 20, and 28 of the '520 patent are infringed, and that claims 1-8 of the '426 patent are infringed. Trial proceeded on the following products: Sterling Ultravision Ci, Sterling Ultravision L, Sterling Ultravision C, Agfa CP-BU, Agfa Ortho HT-G, Sterling Cronex 10T, Sterling Cronex 10TL, Sterling Or-thovision L, Sterling Orthovision G, DI Image Plus Green, and Agfa Ortho Opthos H. Kodak asserts both literal infringement and infringement under the doctrine of equivalents. Defendants have denied infringement and have asserted the defenses of invalidity, non-infringement, laches, and unenforceability, and, with respect to Cronex 10TL, lack of notice under 35 U.S.C. § 287. Kodak furthermore eon-tends that the infringement has been willful, which Defendants deny. Notice as to Sterling Cronex 10TL Kodak has accused both Cronex 10T and Cronex 10TL of infringing the '426 patent. Although denying that Cronex 10TL infringes, Defendants argue that they are not liable for any infringement because Kodak failed to mark its products with the patent numbers of the T-grain patents as required by 35 U.S.C. § 287, that they did not receive notice of infringement by Cro-nex 10TL until after the T-grain patents had expired, and that consequently they cannot be hable for any infringement by that product. Rite-Hite Corp. v. Kelley Co., 56 F.3d 1538, 1549 n. 8 (Fed.Cir.1995) (en banc), cert. denied, 516 U.S. 867, 116 S.Ct. 184, 133 L.Ed.2d 122 (1995). 35 U.S.C. § 287(a) provides generally that where the manufacturer or seller of a patented article fails to mark the article or its packaging with a notice that the item is patented, the patentee shall not be entitled to damages for infringement absent “proof that the infringer was notified of the infringement and continued to infringe thereafter .... ” The section further provides that where the patentee has not marked a patented article, damages for infringement are limited to the period following the date on which the infringer received actual notice of infringement. 35 U.S.C. § 287(a). There is no dispute that Kodak did not mark its X-ray products with a notice that they were patented under one or more of the patents in suit. Kodak has not disputed that for purposes of calculating damages, the damages period commenced when Agfa, or its predecessors in interest, received actual notice of alleged infringement of the patents in suit. Kodak’s original Complaint alleged that Cronex 10T and a number of other Agfa film products infringed Kodak’s '426, '425, and/or '520 patents. Although various products were identified as infringing, the original Complaint did not identify Cronex 10TL as infringing. TX 1040 (¶ 16). It was not until October 24, 2004, ie., after expiration of the T-grain patents, that Kodak supplemented its response to Agfa’s Interrogatory No. 5 and specifically accused Cronex 10TL of infringement. On July 13, 2005, Kodak filed an Amended Complaint and therein accused Cronex 10TL and other products of infringement. TX 1058. In a Decision of July 2, 2004, this Court held that Kodak provided actual notice as to the Cronex 10T product in correspondence to DuPont dated September 7, 1995. The Court further held that the 1995 correspondence did not implicate any other accused product, with the possible exception of Cronex 10TL. The Court found that material disputes of fact regarding similarities between Cronex 10T and Cronex 10TL precluded grant of summary judgment on whether notice as to Cronex 10T was sufficient as to Cronex 10TL as well. Kodak contends that notice it provided Sterling, Agfa’s predecessor in interest, in 1995 regarding infringement by Cronex 10T was sufficient to place Sterling and its assigns on notice that Cronex 10TL infringed the '426 patent. According to Kodak, Cronex 10TL is the latitude version of Cronex 10T and is thus a mere variation of Cronex 10T. Agfa denies that Cronex 10TL is a minor variation of Cronex 10T. Agfa asserts that the September 7, 1995 correspondence did not provide actual notice with respect to Cronex 10TL. According to Agfa, actual notice with respect to Cronex 10TL was not provided until after the T-grain patents had expired, and therefore 35 U.S.C. § 287(a) precludes damages for any infringement by Cronex 10TL. Cronex 10T is classified as a “gradient” film, whereas Cronex 10TL is classified as a “latitude” film. According to Agfa, it was well understood and widely recognized that gradient films were designed for applications requiring clear views of bone but offering little information for diagnostic purposes about the adjacent soft tissues, such as the lungs or mediastinum. TX 1342 (¶ 15); Trial Tr. at 682-83, 685-88, 691-93 (Hurwitz). Latitude films, on the other hand, were widely accepted as designed to capture images from a broader range of exposure levels than a gradient film, e.g., Cronex 10T film. TX 1060 (¶ 32), 1120; Trial Tr. at 682-83, 685-88, 691-93 (Hurwitz), 841-42 (Hudson). The differences in sensitometric properties between the films led to the universally accepted use of the letter “L” in trade names such as Cronex 10TL to denominate latitude films. TX 1060 (¶¶ 34, 35). By letter of September 7, 1995, Kodak notified DuPont that Cronex 10T infringed the '425 and '426 patents, and attached a Cronex 10T brochure. TX 150. By letter of October 11, 1995 DuPont denied infringement and suggested a meeting to discuss the matter. TX 431. Kodak thereafter notified DuPont that it was willing to meet to discuss its infringement concerns. The parties met in November 1995 at DuPont’s facility in Brevard, North Carolina. Two participants at that meeting, Messrs. Hawley and Waaser, testified that only Cronex 10T was discussed at the Kodak/DuPont meeting and that Kodak never mentioned Cronex 10TL at the meeting or in any other communication with DuPont or DuPont’s successor Sterling. Trial Tr. at 514-15, 521-24, 555 (Hawley), 572-73, 576-77, 631 (Waaser). Q. What technical data of films, other than Cronex 10T, was discussed at the meeting? A. No technical data was discussed regarding other films. Q. In fact, you said, Mr. Hawley, you were unaware of any technical data about any film other than Cronex 10T both in September and in November of 1995, correct? A. Personally that’s correct. Trial Tr. at 555 (Hawley). Q. Now, either at the meeting or in this letter, did you provide any coding information or batch numbers for any product other than Cronex 10T? A. No. Trial Tr. at 584-85 (Waaser). The parties agree that DuPont explained at the meeting that it was aware of the T-grain patents, that it designed and manufactured the products to avoid infringement, but that start-up issues at DuPont’s Brevard facility may have caused some out-of-specification product to be produced. DuPont assured Kodak that it had corrected the start-up issues and provided Kodak with production codes so that Kodak could acquire in the market Cronex 10T specimens, determine that their date of manufacture was after the meeting, and conclude that the product did not infringe the T-grain patents. Kodak did acquire and test specimens of Cronex 10T after the November 1995 meeting. Kodak acquired and tested a sample of Cronex 10T in May 1996. There was no testimony about Kodak testing of Cronex 10TL for infringement of the T-grain patents as a result of the meeting. Kodak had in June 1995 tested Cronex 10TL and yet the September 1995 letter accused only Cronex 10T of infringement. TX 150, 1246, 1341 (¶ 214). In an April 9, 2001 letter, i.e., almost six years later, Kodak informed Agfa that it believed that Cronex 10T and ten other Agfa and former Sterling/DuPont products infringed at least one or more of Kodak’s '426, '425, and '520 patents. The April 9, 2001 letter identified eleven film products but made no reference to Cronex 10TL as an allegedly infringing product. TX 432, 1281; Trial Tr. at 641 (Verhoeven), 715-16 (Goedeweeck). The letter identified distinctly denominated products within the same product family, e.g., Ultravision Ci, Ultravision L, and Ultravision C, and Or-thovision L and Orthovision G. Testimony at trial established that it was industry practice to designate latitude films with the letter “L”, so the 2001 letter makes clear that Kodak understood this practice and thus identified specific Ultravision and Orthovision products individually, and not generically by family. “Actual notice requires the affirmative communication of a specific charge of infringement by a specific accused product or device.” Amsted Indus. Inc. v. Buckeye Steel Castings Co., 24 F.3d 178, 187 (Fed.Cir.1994). Resolution of whether notice is sufficient requires a determination of whether “the recipient is informed of the identity of the patent and the activity that is believed to be an infringement.” SRI Int’l v. Advanced Tech. Labs., 127 F.3d 1462, 1470 (Fed.Cir.1997). In Gart v. Logitech, Inc., 254 F.3d 1334 (Fed.Cir.2001), cert. denied, 534 U.S. 1114, 122 S.Ct. 921, 151 L.Ed.2d 886 (2002), cited by both parties, the patentee Gart sent Logitech’s counsel a 1995 letter suggesting that Logitech’s counsel consider Gart’s patent to determine whether a license was needed with respect to TRACKMAN VISTA, a product of Logi-tech. Gart, 254 F.3d at 1337. In a 1996 letter patentee Gart cited its patent to Logitech as “particularly interesting relative to [Logitech’s] trackball product ... being sold under the trademark TRACK-MEN [sic — TRACKMAN] VISTA and TRACKMEN [sic — TRACKMAN] MARBLE.” Id. at 1338. In a 1997 letter, Gart stated it was investigating infringement of “Vista and Marble Trackballs [sic ]” products. Id. Gart filed a complaint in 1998 for infringement by MOUSEMAN, MOUSEMAN+ , TRACKMAN VISTA, TRACKMAN MARBLE, TRACKMAN MARBLE+ , and TRACKMAN MARBLE FX. Id. The Federal Circuit in Gart found that the 1995 and 1996 letters provided actual notice as to TRACKMAN VISTA and TRACKMAN MARBLE, respectively. Gart, 254 F.3d at 1346-47. The Federal Circuit also found that notice was sufficient as to the MARBLE+ , and MARBLE FX products as of the 1996 letter, even though the 1996 letter only mentioned the TRACKMAN MARBLE product. Id. at 1347. However, the letters did not serve as actual notice of infringement with respect to the MOUSEMAN and MOUSEMAN + products. Id. An examination of the predecessor and subsequent decisions does not reveal any further details concerning differences between the various products which might shed more light on the Federal Circuit’s holding. See Tenneco Automotive Operating Co. v. Visteon Corp., 375 F.Supp.2d 360, 365 (D.Del.2005) (citing Gart). The Gart decision has been construed by one district court as follows: [T]he Court cannot accept Defendants’ reading of Gart to foreclose actual notice from ever applying to any infringing product that exhibits anything other than complete and total identity with one cited in the “notice” at issue. Although the Federal Circuit apparently did reject the appellant’s argument that certain allegedly similar (but distinctly denominated) devices were encompassed by the notice provided to the patentee, it did not provide an explanation in support of that holding, and the Court will not ascribe to that rejection a meaning not much as alluded to by the Federal Circuit. See 254 F.3d at 1346-47. Indeed, the Court notes that the Federal Circuit’s statement that “we hold that the district court erroneously found that neither the 1995 letter nor the 1996 letter effected actual notice under section 287, at least as to the products referenced in those letter[,]” suggests an openness to the possibility that certain products not particularly referenced in the subject communications could be held to fall within the charge of infringement levied in the communications. See id. at 1346 (emphasis added). Coca-Cola Co. v. Pepsico, Inc., 2004 WL 4910334 n. 17, 2004 U.S. Dist. LEXIS 30375 n. 17 (N.D.Ga.2004). The district court in Coco-Cola Co. applied what it termed an “intermediate standard” of actual notice: [T]he requirement of notice of infringement directed towards a “specific accused product or device” is satisfied where the accused device is merely a modification or evolution of that referenced in the notice of infringement and fails to exhibit a substantial functional change from the device so referenced. Such a standard, in the view of the Court, pays due regard to the rights of accused infringers to have a sufficiently clear understanding of what “specific product” (as opposed to a “family” or “class” of products) is alleged to be infringing, while at the same time avoiding the imposition upon patentees of the burden of constantly evaluating each embodiment of a competitor’s product to determine whether a minute “tweak” in design mandates a supplemental notice of infringement. Coca-Cola Co., 2004 WL 4910384, at *30, 204 U.S. Dist. LEXIS 30375, at 93-94. Physically, the imaging layers of the Cronex 10T and 10TL were formulated using different silver halide grains. TX 1341 (¶ 211); Trial Tr. at 839-43 (Hudson). From its inception, Cronex 10T had contained a single type — as opposed to a blend — of tabular grains in its imaging layers. Before 1997, Cronex 10T employed a Type 88 grain that had an average grain volume of about 0.24 cubic micron. In 1997, after the DuPont business had been spun off, Sterling began to manufacture a slightly modified version of Cro-nex 10T using Type 78 grains. TX 1341 (¶ 211); Trial Tr. at 839-43 (Hudson). On the other hand, Cronex 10TL had always contained a blend of two different types of tabular grains. Between 1995 and early 1998, Cronex 10TL employed a blend of Type 79 (72% by weight) and Type 81 (28% by weight) grains. TX 1341 (¶ 211); Trial Tr. at 815, 839-43 (Hudson). This version of 10TL existing between 1995 and 1998 is referred to as “Cronex 10TL-old”. In 1998, the grains of Cronex 10TL were replaced with a blend of Type 79LCW and Type 80 grains. The replacement version of the 10TL existing from 1998 forward is referred to as “Cronex 10TL-new”. At no time did the Cronex 10T film contain any of the Type 79, 79LCW, 80, or 81 grains of Cronex 10TL. Cronex 10TL never contained the Type 88 or 78 grains of the Cronex 10T. TX 1341 (¶ 211); Trial Tr. at 839^3 (Hudson). The lower concentration grains blended into the Cronex 10TL-old and Cronex 10TL-new emulsions were of different sizes than the grains of the Cronex 10T emulsion. The different size grains employed in the blends were added to adjust the contrast of the films. TX 832 (¶ 26); Trial Tr. 354 (Dillenbeck). In addition to different grain types, the Type 78 grains of the Cronex 10T and the Type 79 grains of the Cronex 10TL were subjected to different emulsion precipitation procedures. TX 1136, 1341 (¶ 212); Trial Tr. 840-41 (Hudson). The selection of different grain sizes and the different precipitation procedures between the Cronex 10T and Cronex 10TL are responsible for imparting different sensitometry properties to the respective products. TX 1341 (¶¶ 210-222), 1342 (¶¶ 8-23); Trial Tr. at 570-72 (Waaser), 681-83, 692-93 (Hurwitz), 839-43 (Hudson). Radiographic films have three primary photographic properties which are utilized by a radiologist: speed, contrast, and maximum density. TX 1342 (¶ 21). Cronex 10T and Cronex 10TL differed from one another with respect to their contrast and maximum density functionalities. The following table illustrates some of the different properties between Cronex T, Cronex 10TL-old containing Type 79 and 81 grains, and Cronex 10TL-new containing Type 79LCW and 80 grains: TX 1060 (¶ 31). See also TX 1120, 1341 (¶ 213); Trial Tr. at 841-42 (Hudson). Cronex 10T demonstrated a higher contrast and top density (maximum density or Dmax) than the Cronex 10TL product. Contrast describes the relative difference between light and dark areas of developed film. A high contrast film demonstrates sharp differences between the light and dark areas, whereas a low contrast film demonstrates subtle differences between the light and dark areas. The top density indicates the maximum darkness of the film. The toe gradient indicates the contrast achievable by the film at low areas of exposure. The middle gradient indicates the contrast achievable by the film at intermediate areas of exposure. The upper gradient indicates the contrast achievable by the film at areas of high exposure. TX 1120, 1341 (¶ 213), 1060 (¶ 32); Trial Tr. at 841-42 (Hudson). Kodak’s data shows substantial functional differences between Cronex 10T and Cronex 10TL. In June 1995, Kodak conducted photographic performance testing on both Cronex 10T and Cronex 10TL. TX 1246, 1341 (¶ 214). The data shows that the gradient measurements for Cronex 10TL were less at the lower, average and upper points, as compared to Cronex 10T, regardless of the screen used to expose the film. In January 2002, Kodak again studied the photographic properties of Cronex 10T and Cronex 10TL and again found photographic differences between the two films. TX 463, 1246, 1291, 1341 (¶ 214). The functional differences between Cro-nex 10T and Cronex 10TL were also reflected in how Agfa and its predecessors sold and marketed the products. Cronex 10T and 10TL were sold and marketed concurrently with one another for different intended applications. TX 1341 (¶ 211); Trial Tr. at 838 (Hudson). DuPont and Sterling listed Cronex 10T and Cronex 10TL separately in their price catalogues, and DuPont and Sterling described Cronex 10T as a “high contrast” film and Cronex 10TL as a “medium latitude” film. TX 1259. DuPont, Sterling, and subsequently Agfa represented to the end user that Cronex 10T and Cronex 10TL were different products marketed for different uses based on different film properties. TX 1342 (¶ 17). Agfa markets the high contrast Cronex 10T film for applications requiring imaging of minute differences in bone structure. The lower values for the Cronex 10TL film illustrates much broader exposure latitude and is marketed for imaging the fine and dense tissues in the patient’s chest region, such as lung and heart tissues. TX 1060 (¶ 32), 1120; Trial Tr. at 682-83, 685-88, 691-93 (Hurwitz), 841-42 (Hudson). Dr. Robert Hurwitz, a diagnostic radiologist, testified that these products have been received and applied differently by radiologists. Latitude films such as Cro-nex 10TL provide less information about bone detail but significant diagnostic information about the adjacent soft tissues, such as the chest and abdomen, where a wide range of soft tissues and bones are encountered including the lungs, mediasti-num, ribs and spine. TX 1342 (¶ 16); Trial Tr. at 682-83, 685-88, 691-93 (Hurwitz). The testimony of Dr. Hurwitz demonstrated that radiologists appreciated the substantially different functionalities between Cronex 10T and Cronex 10TL, and that radiologists selected between these products based on how these substantial functional differences fulfilled different end user needs. Dr. Hurwitz testified a radiologist would not consider the films to be interchangeable variations of one another. Q. And is it true that in Dr. Dillen-beck’s report he gave the opinion that Cronex 10TL is merely a variation of Cronex 10T? A. He so stated. Q. And, Doctor, from your view point as an end user as a radiologist, do you agree with Mr. Dillenbeck’s evaluation that Cronex 10TL is merely a variation of Cronex 10T? A. I do not. Q. And why is that? A. Because they are two different films for two different purposes. Q. And, Doctor, as a radiologist do you believe that these films are interchangeable? A. I do not. Trial Tr. at 693 (Hurwitz). See also TX 1342 (¶ 22); Trial Tr. at 682-83, 685-88, 691-93 (Hurwitz). Kodak argues that DuPont and Sterling considered Cronex 10T and Cronex 10TL to be “sister products” and part of the same “Cronex 10T family.” TX 153, 158; Trial Tr. 571 (Waaser), 1085-86 (Hudson), at 842 (Hudson); Depo. Desig. Tab 38 (10/14/05 Russell) at 168. This argument is not persuasive because had Kodak intended to make specific charges of infringement in 1995 against products other than Cronex 10T, it could have done so, just as it did in April 2001 when it charged several specific Agfa products by name with infringement. In the alternative, Kodak could have notified DuPont that the family of Cronex products violated its patents, as it did with Agfa in February 2001, when it notified Agfa that its “thoracic imaging products” violated Kodak’s crossover patents. Kodak argues that notice as to Cronex 10T constituted notice with respect to Cro-nex 10TL because of some shared characteristics and processing attributes of the films. Mr. Dillenbeck identified various characteristics and processing attributes for Cronex 10T and Cronex 10TL in advertising brochures that were identically or similarly worded. This argument is not persuasive because Cronex 10T and 10TL also share many identical or similar characteristics and processing attributes to Sterling products which did not use tabular grain emulsions, such as Cronex 10S. TX 125, 126, 140, 141, 1085, 1086, 1099, 1127, 1128, 1341 (¶ 217); Trial Tr. at 438-42 (Dillenbeck). Kodak further argues that its November 10,1995 letter to DuPont (TX 457) expanded notice of infringement beyond the Cronex 10T product. That letter made reference to technical discussions pertaining to “tabular grains in DuPont X-ray film.” The November 10, 1995 letter established a confidentiality agreement between Kodak and DuPont that was to apply at the November 1995 meeting. Q. Well, what other portion of the document mentions any other specific DuPont film that Kodak believed was infringing the '426, '425 or '520 patents that are at issue in this case? MR. FLETCHER: Objection to the extent it goes to attorney/client privilege as to what Kodak was thinking. A. The only film specifically mentioned is Cronex 10T. Q. Nothing else in the letter that would provide DuPont with infringement notice other than the product of Cronex 10T, correct? A. That’s correct. Trial Tr. at 514-15 (Hawley). This Court has already held that: the November 10, 1995 correspondence that Kodak contends is a notice of infringement was nothing more than a letter confirming a meeting to discuss the alleged infringement of Cronex 10T on Kodak’s '425 and '426 patents. The November 10, 1995 letter itself does not charge infringement by any product of any patent, but merely confirms that the parties will meet to discuss “technical data pertaining to tabular grains in DuPont X-ray film and claims in Kodak’s ['425 and '426] patents .... ” The fact that the parties were meeting to discuss DuPont technology in light of Kodak’s intellectual property does not demonstrate that Kodak had put DuPont on notice that all of its T-grain films infringed Kodak’s patents. Moreover, considering the November 10, 1995 correspondence in conjunction with the September 7, 1995 correspondence, as Kodak urges, only supports Agfa’s contention that DuPont received notice of infringement with respect to only its Cronex 10T product. The September 1995 correspondence from Kodak to DuPont, and DuPont’s October, 1995 response discuss only the Cronex 10T product. Accordingly, there is no reason to believe that Kodak’s November 10, 1995 confirmatory letter was intended to expand the scope of the products at issue, given that the parties had engaged in discussions related only to the Cronex 10T film. The fact that Kodak chose to use a generic term in one confirmatory letter can not operate to transform a specific charge of infringement relating to a single product into a significantly broader charge directed at any product that may fit within that generic term. Decision of July 2, 2004. Rather than expanding the scope of notice from its September 1995 letter, the November 10, 1995 letter set forth an understanding that discussions at the meeting would be confidential. Even accepting, arguendo, that the November 10, 1995 letter expanded confidentiality to products other than Cronex 10T, an agreement to maintain communications confidential does not necessarily convey that all products discussed at the meeting were accused of infringement. It also bears mentioning that the confidential information exchanged at the November 1995 meeting was limited to Cronex 10T. Trial Tr. at 555 (Hawley), 584-85 (Waaser). Considering the substantial differences between the products, the industry practice of separately designating products, Kodak’s own letter of 2001 separately identifying specific products within families of products, and the other reasons discussed above, it is my recommendation that notice as to Cronex 10T did not constitute notice of infringement as to Cronex 10TL. Defendants’ Laches Defense Defendants have asserted as a defense that Kodak delayed unnecessarily in bringing suit, so that the equitable defense of laches may be invoked. Establishing laches does not normally preclude suit, but simply limits the period for which damages may be recovered. Laches is a judicially recognized defense to a suit for patent infringement, and Kodak’s claim for damages arising prior to suit may be barred should Defendants establish entitlement to the defense. See A.C. Aukerman Co. v. R.L. Chaides Constr. Co., 960 F.2d 1020, 1028 (Fed.Cir.1992) (en banc). Defendants allege that (1) Kodak delayed filing suit for an unreasonable and inexcusable length of time from the time that Kodak knew or reasonably should have known of its claims against Defendants; and (2) Kodak’s delay operated to the prejudice or injury of Defendants. A.C. Aukerman Co., 960 F.2d at 1032; Costello v. United States, 365 U.S. 265, 282, 81 S.Ct. 534, 5 L.Ed.2d 551 (1961). A delay of six years in filing suit from the time the plaintiff knew or should have known of its claims creates a presumption of laches. A.C. Aukerman Co., 960 F.2d at 1035-36. The parties dispute whether a period of six years passed since Kodak knew or should have known of its claims of infringement. The following is generally undisputed. Kodak sent a September 1995 letter to DuPont (predecessor to Defendants) asserting that DuPont’s Cronex 10T product infringed the '425 and '426 patents. TX 150. After an exchange of correspondence between Kodak and DuPont, a meeting took place in North Carolina on November 18, 1995. TX 828 (¶ 3); Trial Tr. 502 (Hawley). DuPont claimed that it was experiencing start-up difficulties at its then new Brevard facility which may have resulted in a production run tested by Kodak that was out of specification. TX 1046; Trial Tr. at 504, 526-27, 557 (Hawley), 574-78, 581-82 (Waaser), 858-62 (Hudson); Dep. Tr. of Apple 1/29/04 at 25-30, Dep. Tr. of Guy 2/6/04 at 107-109, Dep. Tr. of Braitsch 9/9/04 (30(b)(6)) at 38-40. The meeting concluded by DuPont assuring Kodak that DuPont intended to operate comfortably outside the claims of the T-grain patents, and that any excursions due to “start-up” problems were “fixed.” TX 828 (¶ 4); Trial Tr. 508-09 (Hawley); Depo. Desig. Tab 2 (Apple) at 220. Consistent with the representations at the meeting, DuPont agreed to provide Kodak with film codes for Cronex 10T film produced after the start-up issues at its Bre-vard facility had been corrected so that Kodak could test to assure that DuPont’s assertions of non-infringement were correct. TX 1046; Trial Tr. at 160 (Van Dam), 529-530, 552-553 (Hawley), 581 (Waaser), 858-62 (Hudson). DuPont provided the promised product codes to Kodak in November 1995. DuPont advised Kodak that: “Further, we understand that Kodak will purchase publicly available Cronex 10T with an emulsion number of 578-511x-0161, or later, to confirm that the product is not covered by either of the above identified patents. We assume that once Kodak is satisfied that our product is not covered by either patent, Kodak will drop its charge of infringement.” TX 433, 1256; Trial Tr. at 557 (Hawley), 584-85 (Waaser). In May 1996, Kodak performed grain size measurements on a sample of Cronex 10T that had been made after the batch identified in DuPont’s letter of November 29, 1995. Kodak thereafter analyzed the data from those measurements to compare Cronex 10T to the patent claims. Kodak did not notify DuPont or Sterling of any allegations of infringement as a result of this testing. TX 391, 1258, 828 (¶ 7), 1049 (¶ 7); Trial Tr. at 561 (Hawley), 587 (Waaser); Dep. Tr. of Braitsch 9/9/04 (30(b)(6)) at 39-80. Q. And did Kodak, in fact, analyze a subsequent batch after the 1995 discussions between DuPont and Kodak regarding the alleged infringement by Cronex 10T? A. Kodak did analyze a subsequent batch. Dep. Tr. of Braitsch 9/9/04 (30(b)(6)) at 39. Q. Did the business at Eastman Kodak responsible for making the decision in 1996 whether to sue DuPont over the alleged infringement of Cronex 10T have the subsequent analysis in 1996 of Cro-nex 10T? MR. NOTO: Objection to form. A. I can’t personally say that they had that information. I was told that they had that information. Dep. Tr. of Braitsch 9/9/04 (30(b)(6)) at 41. The grain thicknesses, average aspect ratio, individual projected area and percent total projected area for the Cronex 10T product (578 6011 0070 01) analyzed in 1996 were calculated by Agfa based on Kodak’s data contained in TX 1258. The percent total projected area was calculated from the sum of the projected areas of tabular grains having a thickness of less than 0.2 micron divided by the sum of the projected areas of all grains measured. From Kodak’s data, the average aspect ratio of this subset of grains was 7.04 for those grains having a thickness of less than 0.2 micron and the percent total projected area was 21.10 percent. TX 1060 (i 22). Defendants have represented that these 1996 measurements resulted in at least 50 percent of the total projected area being provided by grains having a thickness of 0.233 micron or less, with the grains having an average aspect ratio of 6.30:1. TX 1060 (¶ 24). Kodak asserts infringement under the doctrine of equivalents for various products where grains of up to 0.246 micron are included to reach the claimed limitation of at least 50% of total projected area. Other products having an average aspect ratio as low as 4.4:1 are also alleged to infringe Kodak’s T-grain patents under the doctrine of equivalents. The calculation for the 1996 Cronex 10T film sample falls within the thickness and aspect ratiorang-es claimed by Kodak to infringe claim 1 of the '426 patent under equivalency. TX 832(¶ 14). Indeed, Kodak has not denied that its claim scope under the doctrine of equivalents encompasses the 1996 Cronex 10T film. See TX 1053 (No. 219). A period of more than six years elapsed between Kodak’s May 1996 testing of the Cronex 10T product and the filing of this action on October 31, 2002. The breadth of the claim scope for which Kodak alleges infringement under the doctrine of equivalents is sufficiently broad to cover the Cro-nex 10T tested more than six years before suit was filed. Defendants have therefore demonstrated that, with respect to Cronex 10T, there was a delay of at least six years in filing suit from the time that Kodak knew or should have known of its claim against Cronex 10T. Accordingly, a presumption of laches applies against Kodak with respect to Cronex 10T. An effect of this presumption is to shift the burden onto Kodak to come forward with sufficient evidence to raise a genuine factual issue regarding the reasonableness of the delay or the absence of prejudice. A.C. Aukerman Co., 960 F.2d at 1037-39. The presumption is of the “double bursting bubble” type in the sense that if Kodak raises a genuine issue of fact with regard to either element, then Agfa must carry the burden of persuasion and affirmatively prove both elements in order to prevail on the defense of laches. Hemstreet v. Computer Entry Sys. Corp., 972 F.2d 1290, 1293 (Fed.Cir.1992). As explained below, Kodak has demonstrated sufficient excuse for its delay to rebut the presumption. Agfa, on the other hand, has not carried its burden of persuasion sufficient to establish entitlement to the defense. Following the November 1995 meeting and its subsequent testing, Kodak made no further allegations of infringement of the T-grain patents to DuPont or its immediate successor Sterling. Trial Tr. at 561 (Hawley), 587, 596 (Waaser), 639 (Verhoeven); Dep. Tr. of Braitsch 9/9/04 (30(b)(6)) at 166-83. The evidence indicates that Kodak’s testing of the 1996 Cronex 10T film in May of 1996 may have provided Kodak with sufficient information to form at least a preliminary opinion that the tested batch of film infringed Kodak’s patents under Kodak’s interpretation of its claims under the doctrine of equivalents. Kodak had accepted DuPont’s explanation and assurances made during the November 1995 meeting. TX 828 (03/02/04 Haw-ley declaration, ¶ 8); Trial Tr. 509 (Haw-ley). However, Kodak relied on DuPont’s representations and assurances that it would permanently fix the manufacturing problems. TX 828 (03/02/04 Hawley declaration ¶ 8); Trial Tr. 509 (Hawley). Kodak’s reliance was not unjustified. Kodak believed DuPont to be a very reputable company. Indeed, the initial samples tested supported DuPont’s representations that the start-up problems had been resolved. Kodak monitored the Cronex 10T film through at least 1998. TX 469,1261; Trial Tr. at 160 (Van Dam); Dep. Tr. of Braitsch 9/9/04 (30(b)(6)) at 132-33, 149. In 1998, Kodak again analyzed a Cronex 10T product sample for grain sizes. TX 1261. As explained by David Braitsch, Kodak’s Intellectual Property Manager for research and development at the time, routine benchmark testing at Kodak in mid-1998 revealed a decrease in silver content in film manufactured by Sterling. TX 829 (03/03/04 Braitsch declaration ¶ 5); Agfa Depo. Desig. Tab 4 (09/09/04 Braitsch) at 31-32. The testing served to arouse Kodak’s concerns. Once Kodak’s concerns were aroused, it investigated the Cronex 10T product and then expanded that investigation. It would seem that Kodak acted reasonably in investigating other products once its concerns about Cronex 10T were aroused. While Kodak could have notified Sterling at the time about the product it then examined, it may well have believed another “manufacturing” issue had arisen. Agfa Depo. Desig. Tab 4 (09/09/04 Braitsch) at 117. Further, Kodak’s individual grain-by-grain thickness analysis of the medical imaging film manufactured by Sterling was necessary for determining infringement under the Kodak T-grain patents. TX 829 (03/03/04 Braitsch declaration ¶ 5). Testing of the other products in suit extended the amount of time required for Kodak to complete its investigation. It was reasonable for Kodak to carry out these tests and, as both parties have attested to, the shadowed electron microscopy technique is time consuming. Trial Tr. 1178 (Liggero) (process is “labor intensive”); Agfa Depo. Desig. Tab 4 (09/09/04 Braitsch) at 136-37. It was also reasonable for Kodak to seek advice of legal counsel before making accusations of infringement against Agfa. Kodak took the time reasonable under the circumstances to review, analyze, and evaluate the Sterling and Agfa T-grain film products in depth before notifying Agfa of its claims for infringement. Agfa’s actions also demonstrate the time commitment involved in conducting an infringement analysis of the T-grain patents. After Kodak sent Agfa a letter regarding infringement of the T-grain patents in April 2001 (less than six years after its original September 1995 notice letter to DuPont regarding Cronex 10T), Agfa by its own admission required a relatively long time to conduct internal discussions regarding the patent infringement allegations due to the complexities of the issues, the need for product testing, collecting of relevant information, and subsequent technical and legal analysis. Trial Tr. 750 (Goedeweeck). It initially took Agfa almost three months to respond to Kodak’s letter regarding the T-grain patents. TX 352; Trial Tr. 749 (Goedeweeck). Agfa continued to request further delays before substantively responding, arguing that it was “premature” to have further discussions in July 2001. Trial Tr. 758 (Goedeweeck). See also TX 241. Kodak first informed Defendants that it believed that Sterling Ultravision Ci, Sterling Ultravision L, Sterling Ultravision C, Agfa Cronex 5, Agfa B Plus, Agfa CP-BU, Agfa Ortho HT-G, Sterling Cronex 10T, Sterling Orthovision L, Sterling Orthovision G, and Agfa Ortho Opthos H infringed at least one or more of the T-grain patents in an April 9, 2001 letter. TX 432, 1281. In response to Kodak’s April 2001 infringement allegations, Defendants informed Kodak that, according to their assessment, none of the products or emulsions were covered by any of the three patents. TX 352, 1282; Trial Tr. at 720-23 (Goedeweeck). As described above, it took Defendants several months to complete their assessment. On September 6, 2001, Agfa and Kodak exchanged technical data on Opthos H, one of the accused products. TX 458,1165, 1284; Trial Tr. at 726-29 (Goedeweeck). On October 29, 2001, Kodak terminated discussions with Defendants. Despite a tradition of handling disputes outside of court, Kodak did not contact Defendants again until over a year later when Kodak filed suit. TX 376, 1288; Trial Tr. at 734-36 (Goedeweeck). While Kodak conceivably could have proceeded more expeditiously after its concerns were aroused, Defendants suggested a product-by-product evaluation during which the parties could air their positions. Hence, Agfa itself was proposing a protracted process to resolve matters. When the 2001 discussions ended, Kodak proceeded to engage counsel and prepare for litigation. Hence, it appears that Defendants seek the benefit of the failed discussions and their own delay, while faulting Kodak for not initially suing in 1996, shortly thereafter, or prior to sending its 2001 letter. Furthermore, this suit involves products other than those produced by DuPont/Sterling. Various Agfa products have been accused of infringement. In short, Agfa would seem to be seeking a piecemeal litigation process which would be overly complicated by requiring that each product’s initial awareness by Kodak be investigated. There is no suggestion that Kodak had significant information about products other than Cronex 10T in 1996, at least not information sufficient to formulate an accusation of infringement against those other products. If Agfa were to have its way, Kodak would be required to file an infringement action after it learned of infringement by any one Agfa product, and to thereafter supplement its complaint every time Kodak initially became aware that an accused product infringes a T-grain patent. This would lead to piecemeal litigation, repetitious discovery and motion practices, and other complications. Moreover, Agfa has not established prejudice or injury. Prejudice can be evidentiary or economic. A.C. Aukerman, 960 F.2d at 1034. While Agfa established that certain participants at the 1995 meeting had in the interim died, it did not establish any meaningful evidentiary prejudice as a result because other participants either testified or gave depositions. Although Dr. Verhoeven, Chairman of Agfa’s Board of Directors, testified that the Sterling acquisition either would not have gone forward or would have been structured differently had he been aware of the infringement issue, he was aware of the issue because the 1995 letter was produced during due diligence in the course of the Sterling acquisition. Despite that, he did not investigate the matter further. Hence, Agfa has not demonstrated any meaningful economic prejudice in its acquisition of Sterling. Additionally, the products in suit involve also Agfa products and not just products produced by Sterling. Finally, laches is an equitable remedy. A luches defense may be defeated if the plaintiff can show that the defendant “has engaged in particularly egregious conduct which would change the equities significantly in plaintiffs favor.” Id. at 1033. While the claims contain limitations other than mere grain thickness, DuPont and Sterling never informed Kodak at or after the 1995 meeting of the to shift to a thinner grain. Potash Co. of Am. v. Int’l Minerals & Chem. Corp., 213 F.2d 153, 155 (10th Cir.1954) (if “the party which advances the defense of laches is responsible for the delay or contributes substantially to it he cannot take advantage of it. Then, too, if material facts are concealed or misrepresented by a suspected wrongdoer, and if in reliance thereon the person wronged is deceived and his suspicions are allayed for awhile, a court of equity will not grant the wrongdoer any advantage resulting from the elapse of time”). The absence of an opinion of counsel is a factor to be considered in determining the appropriateness of laches. Bound v. Spencer Gifts, Inc., 1996 WL 556657, 1996 U.S. Dist. LEXIS 14325 (E.D.Pa.1996) (“a defendant’s failure to make a reasonable inquiry regarding patent validity after being apprised of its existence is a factor to be considered” in determining whether the conduct was egregious to defeat a laches defense); Cover v. Hydramatic Packing Co., 34 U.S.P.Q.2d 1128 (E.D.Pa.1994) (defendant found to have engaged in egregious conduct by continuing to manufacture a product after receiving an infringement notice and without conducting a reasonable inquiry into the validity of the patents). Dr. Verhoeven testified that the 1995 notice letter from Kodak to DuPont was produced during the due diligence phase of Agfa’s acquisition of Sterling, which had by then been spun-off from DuPont. Trial. Tr. at 641. Although he testified that he had assumed the matter concluded by the time of the acquisition, he did not testify to having received any advice from U.S. counsel on the matter. Trial. Tr. at 644. To the extent that the equities were not already balanced in Kodak’s favor by the time required to investigate the various products and the lack of prejudice, Defendants’ failure to obtain legal counsel and their silence concerning the product changes shift the equities in Kodak’s favor. In view of the above, it is recommended that Defendants have not established entitlement to the defense of laches. Defendants’ Invalidity Challenges As in essentially every patent case, the accused infringers assert that the allegedly infringed claims are invalid in view of prior art. As the party asserting invalidity, Defendants* burden is one of clear and convincing evidence. 35 U.S.C. § 282. “A patent issued from the United States Patent and Trademark Office (PTO) bears the presumption of validity under 35 U.S.C. § 282. An accused infringer, therefore, must prove patent invalidity under the clear and convincing evidentiary standard.” Metabolite Labs., Inc. v. Laoratory. Corp. of Am. Holdings, 370 F.3d 1354, 1365 (Fed.Cir.2004), cert. denied, 548 U.S. 926, 126 S.Ct. 2976, 165 L.Ed.2d 990 (2006). Moreover, it is “especially difficult” to satisfy the burden of proving invalidity when prior art cited in litigation was previously considered by the PTO during prosecution. Hewlett-Packard Co. v. Bausch & Lomb, Inc., 909 F.2d 1464, 1467 (Fed.Cir.1990). Prior art may render claims invalid as “anticipated” under 35 U.S.C. § 102 or as “obvious” under 35 U.S.C. § 103. Anticipation requires that each and every element of the claimed invention be disclosed in a single prior art reference. In re Paulsen, 30 F.3d 1475, 1478-79 (Fed.Cir.1994). Obviousness requires that “the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains.” 35 U.S.C. § 103. “[A] patent composed of several elements is not proved obvious merely by demonstrating that each of its elements was, independently, known in the prior art.” KSR Int’l Co. v. Teleflex Inc., - U.S. -, 127 S.Ct. 1727, 1741, 167 L.Ed.2d 705 (2007). “[I]nventions in most, if not all, instances rely upon building blocks long since uncovered, and claimed discoveries almost of necessity will be combinations of what, in some sense, is already known.” KSR, 127 S.Ct. at 1741. Kodak sold a commercial X-ray film product containing chemically sensitized, tabular grain emulsions since the 1930’s. From 1937 until the 1950’s the Eastman Kodak Company sold a Duplitized® ra-diographic film product under the name No-Screen X-Ray Code 5133. The product contained as coatings on opposite major faces of a film support sulfur sensitized silver bromide emulsions. Since the emulsions were intended to be exposed by X-radiation, they were not spectrally sensitized. The tabular grains had an average aspect ratio in the intermediate range of from about 5 to 7:1. The tabular grains accounted for greater than 50% of the projected area while nontabular grains accounted for greater than 25% of the projected area. TX 312 ('520 patent, col. 8, l. 66, to col. 9, l. 15); TX 320 ('425 patent, col. 1, l. 62, to col. 2, l. 12); TX 313 ('426 patent, col. 1, l. 62, to col. 2, l. 13); Trial Tr. at 1101 (Liggero). One cannot conclude from the foregoing statement that the No-Screen X-Ray Code 5133 emulsions met the grain structure and other parameters of either the intermediate or the high aspect ratio claims. TX 835 (10/26/06 Marchetti report, ¶ 36); Trial Tr. 1147 (Liggero) (none of the claims of the patents in suit call for an emulsion with an average grain thickness of 0.36 micron which is a characteristic of No-Screen according to the T-grain patents). Further, No-Screen was not spectrally sensitized. TX 835 (10/26/06 Marchetti report, ¶ 37). See also Trial Tr. 1146 (Ligge-ro). Nothing about No-Screen would have prompted or encouraged a person skilled in the art to investigate spectral sensitization of tabular grains. TX 835 (10/26/06 Marchetti report, ¶ 37). As the above text indicates, No-Screen was not spectrally sensitized because it was intended to be exposed to X-ray-radiation (not to light from intensifying screens, as is the case for the films at issue in this litigation). Id; Trial Tr. 1146 (Liggero). Moreover, Kodak specifically referred to the No-Screen product in the patent applications and brought the product to the attention of the patent examiner in an Information Disclosure Statement. TX 1009 (at EK027144). It is “especially difficult” to satisfy the burden of proving invalidity when prior art cited in litigation was previously considered by the PTO during prosecution. Hewlett-Packard, 909 F.2d at 1467. C. Mees & T. James, The Theory of the Photographic Process (3d ed.1966), Figure 2.6 (“Mees and James”) is widely accepted as the authoritative work of the photographic sciences. “The Mees and James book ... is widely read and in many ways the Bible of photographic science.” TX 1025; Trial Tr. at 1108, 1111 (Liggero). Mees & James Fig. 2.6 is described as showing “[p]reshadowed carbon replicas of grains of a high-speed negative-type emulsion.” TX 846 (Mees & James at 37). It is a single-field image. TX 835 (10/26/06 Marchetti report, ¶ 38). The text referring to this Figure states that “[t]he grains of commercial emulsions (Figs. 2.5 and 2.6) are rarely larger than 5 jjl; a more normal upper limit for very fast emulsions is half that value.” TX 846 (Mees & James at 36). Using the disclosed shadow angle of 11 degrees and ignoring sampling and measurement error, Agfa’s expert Dr. Liggero measured 42 grains in Figure 2.6 and concluded that the depicted emulsion contains tabular grains of less than 0.3 micron in thickness and at least 0.6 micron in diameter that account for about 89 percent of the total projected area and have an average aspect ratio of about 11.5:1. TX 1025A, 1169; Trial Tr. at 1110-11 (Liggero). Dr. Liggero’s measurement protocol and the photograph of Figure 2.6 of Mees & James are not sufficiently reliable as to constitute clear and convincing evidence of invalidity. First, the number of grains measured by Dr. Liggero is insufficient to clearly and convincingly constitute a reliable sampling population for determining whether the Mees and James emulsion has a high aspect ratio as required by the '425 and '520 patents or an intermediate aspect ratio as defined by the '426 patent. According to a document generated by an Agfa affiliate in 1987, only 30 of the grains in this image can be measured. TX 76 (“The micrograph ... has several crystals that cannot be measured because they overlap leaving 30 crystals in the field”); Trial Tr. at 1149-50 (Liggero). Despite that, Dr. Liggero testified that he was able to measure as many as 42 grains. Trial Tr. at 1110 (Liggero); Depo. Desig. Tab 31 (02/13/07 Liggero) at 164. Dr. Liggero himself stated, however, that 42 grains is an insufficient number of grains from which to draw a conclusion about whether the emulsion falls within the literal scope of any of the T-grain patents. Trial Tr. 1110,1150,1200 (Liggero) (“To draw rigorous scientifically accurate conclusions, one would need more than 30 or 42 samples .... ”). Second, the quality of the photograph in Mees and James draws Dr. Liggero’s measurements into question. According to Dr. Liggero, to “draw rigorous scientifically accurate conclusions, ... one would want the original and standard TEM.” Trial Tr. 1200. Dr. Liggero also testified that he was not sure whether the image somehow had been changed from the original as a result of its being reproduced for bookmaking purposes. Trial. Tr. 1198. Dr. Liggero indicated that his measurements from the textbook were sure to include distortion error. Trial Tr. 1111. Third, Dr. Liggero’s conclusions that the emulsion shown in Figure 2.6 of the Mees and James reference was chemically and spectrally sensitized were based on text that the emulsion was a commercial emulsion. Dr. Liggero stated that the emulsion was “most likely optimally chemically and spectrally sensitized.” Trial Tr. at 1108— 11 (Liggero). This testimony concerning “likely” optimum sensitization does not rise to the level of confidence necessary for satisfying a clear and convincing burden. Recall that No-Screen, a tabular grain product, was commercially available and yet was not spectrally sensitized. Kodak’s expert witness Dr. Marchetti asserted that Mees & James Fig. 2.6 does not teach anything about sensitization of T-grains. TX 835 (10/26/06 Marchetti report, ¶ 40). Kodak represented during the reexamination proceedings that the emulsion shown in Mees & James Fig. 2.6 was a research emulsion and was not spectrally sensitized. TX 423 (affidavit submitted by Kodak in the '426 reexamination). Dr. Liggero stated that he had no reason to doubt the accuracy of Kodak’s statements. Trial Tr. 1187-88 (“I have no reason to believe that Kodak’s statement to the Patent Office in the '426 re-exam wasn’t accurate.”). Finally, the '426 patent was subjected to reexamination by the PTO. Mees & James Fig. 2.6 was before the PTO in the Reexamination of the '426 patent. Trial Tr. 1147-48; Depo. Desig. Tab 31 (02/13/07 Liggero) at 142. The statutory “presumption [of validity] is fortified to the extent that there has been a reexamination of the patent by the Patent and Trademark Office.” CVI/Beta Ventures, Inc. v. Custom Optical Frames, Inc., 893 F.Supp. 508, 514 (D.Md.1995), aff'd, 92 F.3d 1203, 1996 WL 338388 (Fed.Cir.1996); E.I. du Pont de Nemours & Co. v. Polaroid Graphics Imaging, Inc., 706 F.Supp. 1135, 1141 (D.Del.1989) (while presumption of validity remains unaltered, “the exhaustive consideration given the prior art by the PTO during [reexamination] must be weighed in determining patentability”), aff'd, 887 F.2d 1095, 1989 WL 108217 (Fed.Cir.1989). The James and Higgins reference in Figure 2.3 depicts a “typical negative-type” silver iodobromide tabular grain emulsion. According to Agfa, the reference therefore describes to a person of ordinary skill in the art a commercial optimally chemically and spectrally sensitized tabular grain film. TX 1021A; Trial Tr. at 1114-16 (Liggero). Agfa further argues that using the disclosed shadow angle of 18.4 degrees and ignoring sampling and measurement error, Figure 2.3 depicts an emulsion containing intermediate aspect ratio T-grains as defined by the '426 patent claims. During cross-examination Dr. Liggero acknowledged that Fig. 2.3 of James and Higgins was prepared from the same electron micrograph as Figure 2.6 of Mees and James. Trial. Tr. 1165 (Liggero). Dr. Liggero also stated that he could not find any reason to doubt Kodak’s statement to the PTO that the sample was mislabeled and was not a commercial sample. Trial Tr. 1188 (Liggero). Clear and convincing evidence requires more than assumption. As the party asserting invalidity, it was incumbent upon Defendants to provide evidence that was both clear and convincing about the James and Higgins material. Defendants have not met this burden. G. Danguy, “On the Sensitometric Character and Chemical Sensitization of Silver Bromide Emulsions with Tabular Grains,” Science et Industries Photographiques, Vol. 34, No. 5-6, at 141-50 (1963) (TX 1024) (“Danguy 1963”), was cited by Kodak for consideration by the PTO during prosecution of the '520 patent. See TX 321 (EK004997-5005), 1009 (EK027143-46) (Cited Art Statement Under 37 CFR 1.97-1.99). Kodak characterized Danguy as follows: Danguy can be viewed as being essentially cumulative with de Cugnac and Chateau, cited in the specification at page 2, lines 21-26, in that it also discloses high aspect ratio tabular grain silver bromoiodide emulsions. Danguy further discloses chemical sensitization of high aspect ratio tabular grain emulsions, which de Cugnac and Chateau does not. TX 321 (EK005000), 1009 (EK027146). Danguy 1963 is an elaboration of a study first reported in G. Danguy, “The Preparation and the Sensitometry of Photographic Emulsions with Tabular Silver Bromide Grains,” Bulletin de la Societé Rovale des Sciences de Liège, Vol. 31, No. 11-12, at 732-50 (1962) (TX 364) (“Danguy 1962”). See TX 835 (10/26/06 Marchetti report, ¶ 12). Danguy 1962 and Danguy 1963 describe the preparation of five em