Illustrated Book Study: Digital Conversion Requirements of Printed Illustrations Anne R
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Illustrated Book Study: Digital Conversion Requirements of Printed Illustrations Anne R. Kenney and Louis H. Sharpe II with Barbara Berger, Rick Crowhurst, D. Michael Ott, and Allen Quirk July 1999 RELIEF INTAGLIO PLANOGRAPHIC Wood Engraving Photogravure Collotype Report to the Library of Congress Preservation Directorate Contract # IN97C-22/97CLCCT7021 Contractors Cornell University Library, Department of Preservation and Conservation, Ithaca, NY Picture Elements, Inc., Berkeley, CA Cover illustration: The authors intentionally chose representative eyes from the various book illustrations as a tribute to James M. Reilly, Director of the Image Permanence Institute. In his “Flowchart for Identification Guide,” Care and Identification of 19th Century Prints (1996), Reilly used photomacrographs of eyes to illustrate the differences among various 19th century photographic prints. This chart is available at: http://www.rit.edu/~661www1/FRAMESET.html. Table of Contents TABLE OF CONTENTS ..................................................................................................................................... 3 ABSTRACT.......................................................................................................................................................... 5 1.0 INTRODUCTION ......................................................................................................................................... 6 2.0 PROJECT METHODOLOGY...................................................................................................................... 6 2.1 SELECTING SAMPLE PAGES ........................................................................................................................... 6 TABLE 1. COMMON BOOK ILLUSTRATIONS OF THE 19TH AND 20TH CENTURIES ................................................... 7 2.2 CHARACTERIZING THE ATTRIBUTES OF DIFFERENT ILLUSTRATION PROCESS TYPES AT VARIOUS LEVELS............................................................................................................................................................. 10 2.3 MAPPING ILLUSTRATION PROCESS TYPES TO ELECTRONIC CONTENT TYPES ................................................. 10 2.4 DIGITIZING SAMPLE PAGES ......................................................................................................................... 11 2.5 EVALUATING SAMPLE IMAGES.................................................................................................................... 11 2.5.1 Structure ............................................................................................................................................. 12 2.5.2 Detail................................................................................................................................................... 12 2.5.3 Essence ............................................................................................................................................... 13 2.5.4 Print Evaluation................................................................................................................................... 14 2.6 INVESTIGATING METHODS FOR AUTOMATIC DETECTION OF ILLUSTRATION CONTENT REGIONS .................... 15 2.6.1 Introduction ........................................................................................................................................ 15 2.6.2 Background......................................................................................................................................... 15 2.6.3 A Possible Strategy for Identifying Illustration Regions........................................................................ 15 2.6.4 Document Understanding.................................................................................................................... 16 2.6.5 Detecting Text Regions........................................................................................................................ 16 2.6.6 Conclusion.......................................................................................................................................... 16 2.7 INVESTIGATING AUTOMATIC METHODS TO DISCRIMINATE DIFFERENT ILLUSTRATION PROCESS TYPES.......... 17 2.7.1 Introduction ........................................................................................................................................ 17 2.7.2 Necessary Distinctions ........................................................................................................................ 17 2.7.3 Possible Characteristics for Classifying Illustration Processes............................................................. 17 2.7.4 The Special Case of Halftones ............................................................................................................. 18 2.7.5 Conclusions on Discriminating Illustration Process Types................................................................... 18 2.8 INVESTIGATING METHODS FOR PROCESSING DIFFERENT ILLUSTRATION TYPES............................................. 20 2.8.1 Introduction ........................................................................................................................................ 20 2.8.2 Possible Image Processing Steps ......................................................................................................... 20 2.8.3 General Concepts................................................................................................................................ 21 2.8.4 Common Processing Steps................................................................................................................... 21 2.8.5 Halftone Illustration Regions............................................................................................................... 21 2.8.6 Soft Process Illustration Regions ......................................................................................................... 22 2.8.7 Fine-Featured Hard Process Illustration Regions ................................................................................ 22 2.8.8 Hard Process Illustration Regions ....................................................................................................... 22 2.9 AN EXAMPLE UTILITY FOR HALFTONE PROCESSING..................................................................................... 23 2.10 TESTING AND VERIFYING THE PROCESS..................................................................................................... 25 2.10.1 Full Resolution View ......................................................................................................................... 25 2.10.2 Derivative Creation........................................................................................................................... 26 2.10.3 Printing............................................................................................................................................. 27 2.10.4 Other Observations ............................................................................................................................ 27 2.10.5 Compound Documents....................................................................................................................... 27 2.10.6 Desirable Enhancements to the Utility ............................................................................................... 28 3.0 CONCLUSIONS.......................................................................................................................................... 28 Illustrated Book Study, Page 3 REFERENCES................................................................................................................................................... 30 APPENDIX 1. ADVISORY COMMITTEE MEMBERS................................................................................. 31 LIBRARY OF CONGRESS AFFILIATION................................................................................................................. 31 CORNELL UNIVERSITY AFFILIATION .................................................................................................................. 31 APPENDIX 2. HALFTONE UTILITY USER’S MANUAL ............................................................................ 31 Illustrated Book Study, Page 4 Abstract The Cornell University Library Department of Preservation and Conservation and Picture Elements, Incorporated undertook a joint study for the Library of Congress to determine the best means for digitizing the vast array of illustrations used in 19th and early 20th century commercial publications. This work builds on two previous studies. A Cornell study[1] characterized a given illustration type based upon its essence, detail, and structure. A Picture Elements study[2] created guidelines for deciding how a given physical content region type should be captured as an electronic content type. Using those procedures, appropriate mappings of different physical content regions (representing instances of different illustration processes) to electronic content types were created. These mappings differed based on the illustration type and on the need to preserve information at the essence, detail, or structure level. Example pages that are typical of early commercial illustrations were identified, characterized in terms of the processes used to create them (e.g., engraving, lithograph, halftone), and then scanned at high resolutions