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IGI Selected in Cornell's Digital to Microfilm Brittle Books ProjectStephen Chapman Image Graphics, Inc. of Shelton, Connecticut has been awarded a contract by Cornell University to create raster Computer Output Microfilm (COM) directly from digital image data of books with brittle pages. Why is this important? A substantial number of the nation's print and non-print research materials are deteriorating. The Association of Research Libraries estimates that 75 million volumes in U.S. research libraries are endangered due to brittle and/or highly acidic paper. This problem of deteriorating research materials extends beyond printed books to archival materials, where one estimate indicates that more than 2.5 billion pages in the nation's archives are vulnerable to loss through chemical deterioration, To be preserved on microfilm, a stable archival medium, these pages may be reformatted by photographic or digital processes. If the choice is made to use scanning as the reformatting method, then to convert the digital data into microfilm that meets preservation standards for quality and permanence, Image Graphics' digital-to-film conversion services offer the highest quality imagery attainable on microfilm. Cornell is conducting a two year demonstration project, funded in part by the National Endowment for the Humanities, to develop an effective model process to create microfilm that meets national preservation standards for quality and permanence when using digital technology as the capture method. (For a project description and an overview of the potential in using the hybrid approach-- digital technology and microfilm--for preservation reformatting, see the enclosed copy of Anne R. Kenney and Martha J. Hanson's article, "Cornell University Seeks Service Bureaus For Digital To Microfilm Project," from Imaging Service Bureau News 8 (2), March/April 1994, p. 1, 6-7.) As part of this project, Cornell is scanning 1,500 books at 600 dpi using the Xerox Document on Demand system, and contracting out the production of 35mm preservation COM. A description of the process followed by Cornell and the results to date follows. An RFP for COM services was developed and sent to two dozen imaging service bureaus in June 1994. Approximately ten vendors expressed an interest in the project. Each was asked to prepare a sample roll of film from TIFF images for five books. In August, a technical advisory committee of nationally recognized experts in the fields of imaging science, micrographics, and standards development met at Cornell to review proposals, inspect sample film, and conduct Conference calls with potential vendors. The advisory committee members 'Included: Paul Conway, Head, Preservation Department, Yale University; Nancy Elkington, Assistant Director, Preservation Services, Research Libraries Group; 'Michael Lesk, Division Manager, Computer Sciences Research, Bellcore; Don Williams, Senior Image Engineer, Research Laboratories, Eastman Kodak Company; and Don Willis, Vice President of Electronic Publishing, INET. During the extensive review process, the committee considered the overall quality of proposals, technical capabilities of the vendors, quality control measures, and consumer/vendor relations. Following negotiations regarding various technical issues, quality control procedures, and microfilm storage requirements, Image Graphics was chosen as the sole vendor for the project. The conversion services are being carried out by a new division of Image Graphics, the Image Graphics Recording Center IGRC). Using the Micrographics EBR System 3000 electron beam recorder (EBR) manufactured by Image Graphics, the IGRC records the bitmapped images directly from 8mm Exabyte tapes to Kodak ImageLink HQ 35 mm microfilm, which is widely used in preservation microfilming. The EBR software controls the reduction ratios, density, image placement, and required spacing (between images, frames, and volumes) on each roll of film. Although the Micrographics EBR System 3000 is capable of processing digital data up to 1,000 dpi at 24X, the specifications for the Cornell project have been set to 600 dpi, with variable reduction ratios ranging from 6X to 1OX. With these EBR settings, IGRC reports recording speeds of less than four seconds per page. In accordance with their contract, in the beginning of December, IGRC delivered three rolls of master negative film from 19 books to Cornell for inspection. The film had passed the IGRC quality control inspections as well as third party testing for the presence of residual thiosulfate (methylene blue tests). Cornell performed a full frame by frame light box inspection of each roll to verify that the film quality meets current and emerging technical specifications for preservation. The results of the inspection at Cornell are:
With the advice of the project technical advisory committee, Cornell is using two technical targets to measure resolution. In contrast to light lens processes, resolution via digital technology is judged in the following ways:
The technical test targets used in tandem at Cornell to evaluate text resolution are: the RIT Alphanumeric Test Object, and the AIIM Scanner Test chart #2. At 600 dpi output, the rendering of text on the microfilm images of the targets is as follows:
These results compare favorably, and in some cases exceed, the quality of film produced in commercial microfilm cameras, particularly in the rendering of halftones. The project continues through March 1996. Yale University is conducting a complementary project in which digital images are created from preservation microfilm. Comparative data is being collected in the two projects for image quality, conversion processes, and costs. The Cornell and Yale projects will benefit the preservation community as it seeks to understand the circumstances under which scanning first or filming first are the most appropriate in achieving the goals of preservation and enhanced access through the use of digital technology.
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