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Guides to Quality in Visual Resource Imaging
July 2000
� 2000 Council on Library and Information Resources
Contents
Background
Introduction
1. Planning an Imaging Project, by Linda Serenson Colet, Museum of Modern Art
2. Selecting a Scanner, by Don Williams, Eastman Kodak Company
3. Imaging Systems: the Range of Factors Affecting Image Quality, by Donald D'Amato, Mitretek Systems
4. Measuring Quality of Digital Masters, by Franziska Frey, Image Permanence Institute Rochester Institute of Technology
5. File Formats for Digital Masters, by Franziska Frey
References & Further Reading
About the Authors
Background
In 1998, the Digital Library Federation, the Council on Library and Information Resources, and the Research Libraries Group created an editorial board of experts to review the state of the art in digital imaging of visual resources (original photographs, prints, drawings, maps, etc.). While sources for instruction in digitizing text or text and images existed and were growing, none specifically addressed the challenges of two- and three-dimensional, as well as color-intensive, materials.
Charged to identify imaging technologies and practices for such visual resources that could be documented and recommended, the board arrived at a set of guides in the science of imaging—objective measures for image qualities and how they can be controlled in various aspects of the imaging process. With detailed outlines created by board members, DLF and CLIR commissioned board-recommended authors, and have published the guides on the Web with RLG.
These five guides are designed to serve the growing community of museums, archives, and research libraries turning to imaging as a way to provide greater access to their visual resources while simultaneously preserving the original materials. They will be updated periodically. Your comments are encouraged by DLF and RLG.
Introduction
Museums, archives, and libraries worldwide are converting visual resources into digital data, and in each case managers of those conversion programs face the same series of decisions about how to create the best possible image quality. These guides bring together the expertise and experience of leaders in the field of visual and color imaging and make their knowledge widely accessible.
The guides are written for those who have already decided what they will digitize and what purposes the digital images will serve. After the often-complex matters of selection have been settled, these guides address the steps to successfully create and store high-quality digital masters and derivatives. They include project planning, scanner selection, imaging system set-up, and the resulting digital masters.
Guide 1, planning, underscores the importance of defining the users' needs and requirements before undertaking the project. Best practices in digital visual resources include creating images that meet quality and use objectives and documenting how the image being delivered was created. Guide 2, finding the right scanner, starts from a knowledge of the source material to be scanned and, by looking at how to interpret product specifications and employ verification tests, equips users to evaluate new machines as well as those now on the market. Similarly, for setting up the larger system of scanner, camera, operating system, and image-processing software, guide 3 provides information, techniques, and procedures that can be used now and into the future. Guide 4 deals with digital masters, focusing on developing "visual literacy" in digital imagery and quality assurance; and guide 5 addresses the effect that different file formats—the containers—have on the performance and persistence of digital masters over time and technological change.
While there are few universally applicable answers to the questions faced by those who plan and carry out visual imaging projects, the writers of these guides identify critical decision-making points and offer concrete guidance based on the purposes of the images. Where possible, they provide objective measurements of image quality. At the same time, they flag areas where further research and testing are needed before specific practices can be recommended. Each guide is a module that can stand on its own to be mined for information. As a set, the guides provide guidance on how to find what you need to accomplish your stated goals with the available technology, whatever its state of evolution. And they help to clarify the consequences of trade-offs that all managers must make to stay within their means.
In providing this framework, from planning to digital output and perpetuity, this publication is intended to offer value both to practitioners and to those who must judge whether a digital imaging effort is feasible, well planned, and worth supporting.