Digitizing Images Stephen Chapman Weissman Preservation Center Harvard University Library 30 September 2003

1. Digitizing Images Stephen Chapman Weissman Preservation Center Harvard University Library 30 September 2003

12. Motivations Necessity More and more material is being produced in digital form; more and more of our users want access to such materials. Excellence Because we value the highest levels of teaching and research we will have to change our way of doing things. Innovation Technology enables uses not possible with analog formats. Obligations are to create coherent, integrated collections and to deliver them with tools that support innovative professional practice.

13. Why images? “The special opportunities presented by digital technologies constitute the most fundamental development in the potential for increased access and flexibility of use since the advent of photographic reproduction.” Neil L. Rudenstine, April 2001

15. Digital technologies World Wide Web “This is what the Internet does well.” Relational databases Permit flexible approaches to cataloging — hierarchical structures needed to manage and describe multiple versions of a particular item, including surrogates. Digital cameras and scanners Proven capability to create digital surrogates “that faithfully represent the originals in tone and color and provide a level of detail that would enable advanced study.” David Remington

19. Products of image digitization Images The data for scholars to study. Single version of image rarely suffices to meet all needs (compare, study, print). Descriptions of images (text) The “metadata” the user needs to locate and interpret images. Descriptions of ownership and rights (text) The metadata the owner uses to disclose terms and conditions associated with using images. Source materials The principal assets valued by owners and users.

20. Infrastructure Catalogs Systems for comprehensive and controlled searching. Persistent naming Means to ensure image management and reliable access. Repository A trustworthy place to manage images over time. Delivery Systems to deliver digital images to authorized users.

21. planning selection prep cataloging imaging deposit linking Workflow project source surrogates

22. Project planning There are no absolute rules for creating good collections, objects or metadata. Every project is unique and each has its own goals. The key to a successful project is not to follow any particular path, but to think strategically and make wise choices. IMLS Framework of Guidance

23. Selection For the kind of pictures we collect, individual public domain analysis is expensive. [T]here is only one practical methodology: accession policy must choose the most conservative boundary as a functional bright line that separates what is acceptable and what is not acceptable. Robert A. Baron

24. Prep Whenever there is handling of original collections, there is a need for the application of conservation knowledge and practice. Library of Congress NDLP and Conservation Division

25. planning selection prep cataloging imaging deposit linking Workflow project source surrogates

26. Cataloging practices Local, but… “Picture catalogs still tend to be incomplete, idiosyncratic, and isolated.” Helena Zinkham Movement to consolidate: union catalogs AMICO, ArtSTOR, VIA, UCAI(UCSD, ArtSTOR, Harvard) Emerging consensus and best practice VRA Guide, “Cataloguing Cultural Objects” http://www.vraweb.org/CCOweb/ Data standards “promote sharing, improve the management of content, and reduce redundancy of effort.”

27. Descriptive metadata standards Specific to topics or disciplines Biology or art Specific to kinds of materials Moving pictures, encoded texts Specific to support particular functions Discovery, rights management, presentation

28. Descriptive metadata standards • Which “information pieces” • Data dictionaries (e.g., for OLIVIA) • CDWA, VRA Core, Dublin Core • How information is formed • Content standards and vocabularies: • VIA Working Group has identified over 20 • How information is encoded for processing • Syntax (e.g., MARC, RDF) • Virtually no standards govern all of these aspects of metadata. • http://hul.harvard.edu/ois/systems/via/via_standards.html

29. Key decisions Scope Which catalog(s)? …HOLLIS, OASIS, VIA used at Harvard Item- or group-level cataloging Extent Amount of cataloging (project and program policies)

30. Digital image production • Lights, camera… • Visual literacy and technical skill still absolutely critical • Pixels! • “The more one looks at image quality and ways to clearly • define it, the more parameters have to be taken into account.” • Frey and Reilly • - rendering intent • - tone reproduction • - detail and edge reproduction • - color reproduction • - noise

31. Digital image standards • Formats • DLF Global Digital Format Registry • Quality • I3A/IT10 Electronic Still Picture Imaging Committee • ISO speed, resolution (MTF), OECF, noise and color measurement • ISO 3664: 2000 Viewing conditions • Technical metadata for digital still images • NISO Z39.87-2002 AIIM 20-2002 (governed by LC)

33. Digital imaging practices masters delivery images admin metadata quality control “support intended current and likely future use” (IMLS Framework) archival masters (optimized for processing, not viewing) production masters (optimized for automation) no compression for grayscale and color images TIFF = format of choice

34. Digital imaging practices masters delivery images admin metadata quality control calibrated devices calibrated environment targets checksums validation software at repository

35. Digital imaging practices masters delivery images admin metadata quality control • “supports management of resources”(R. Wendler) • ownership • access restrictions • technical attributes of files • XML format • produced and deposited in addition to images

36. Digital imaging practices masters delivery images admin metadata quality control calibrated devices calibrated environment targets checksums validation software at repository

37. Deposit DRS preservation services provide active oversight to ensure an indefinite lifespan for objects deposited in approved formats. "Oversight" involves monitoring file formats, assessing the vulnerability of digital collections, and transforming files to maintain usability. HUL DRS Policy Guide

38. Current cost gap: digital 53-157X more expensive than film @ OCLC 18-52X more expensive at Harvard (DRS)

39. Current cost gap: digital 209X more expensive than film @ OCLC, 70X more expensive at Harvard (DRS)

40. Closing cost gaps for repository storage Compression Investigate risks associated with using bit-for-bit lossless compression instead of uncompressed formats as preservation masters. Cost metrics Bill owners at unit other than size (e.g., per GB) to sustain costs of running repository and preservation services. Subsidies Create common-good repositories and services (“safe havens”) with secure, sustainable funding lines for items that meet defined criteria.

41. Hybrid approach viable for still images Digital Masters Deposit digital master to repository, pay for annual maintenance regardless of use. Repurpose digital masters: produce delivery images, in analog or digital formats, in advance and/or upon request. Analog Masters Deposit analog (e.g., film) master to repository, pay for annual maintenance regardless of use. Repurpose analog masters: produce delivery images, in analog or digital formats, in advance and/or upon request.

42. Lessons learned Building ArtSTOR into a trusted repository … will require not only time and resources, but also collegiality and the active participation of individuals from academic institutions, museums, libraries, and research centers; specialists in imaging and in building databases; others experienced in the creation of digital resources; experts in intellectual property rights; and wise generalists. One clear conclusion is that working on this project inspires humility! William G. Bowen, President Andrew W. Mellon Foundation

43. Resources • Your colleagues! • Mellon Foundation, 2001 President’s Report, “ArtSTOR” • Harvard University Library, LDI Program Origins • David Remington, “HCL-DIG General Imaging Practice” • Helena Zinkham,”Bridges & Whirlpools: Best Access Practices for Pictures”