Guidelines: Content Categories and Subcategories Objectives:
Reformatting Historical Printed Matter, Documents and Manuscripts,
and Pictorial Materials — Content Categories and Subcategories Table
Still Image Working Group

Use Cases: Master Images and Image Sets

• Digitizing organization uses archival or production master image(s) to produce derivative images for the use cases listed under the tab to the right.
• Digitizing organization uses the master (or migrated copies) to create a virtual replica of the original item in the event of its loss, deterioration, or de-accessioning.
• Digitizing organization (or successor/receiving agency with an archiving mission) sustains the master (or migrated copies) for the long-term without loss of essential features.
• Digitizing organization uses masters for disaster recovery in the event of impairment of digital asset management systems.

Quality Notes

• Image-quality characteristics of the archival or production master image(s) must be sufficient to support the production of the various image types listed under the Derivative Images tab. Dependencies include appropriate image specifications and a production activity that applies appropriate process controls, e.g., the use of targets to monitor output, a quality assurance process that includes the use of color profiles, calibrated monitors and viewing environments, and various automated tools.
• For future exploration: When should master images be in an original-referred image state?
• Image-quality characteristics as above plus framing (capture of what curators define as the whole object) must be sufficient to permit the use of the master (or migrated copies) to create a physical replica of the original item in the event of loss or deterioration. That is, the master will fill the niche formerly filled by copy negatives and copy transparencies.
• Image-quality characteristics and completeness of coverage, plus selection of sustainable digital-content formats must be sufficient to permit sustaining or migrating the master over the long-term without loss of essential features.
• Disaster recovery in the event of the impairment of digital asset management systems depends upon the availability of metadata in standardized formats, including descriptive, administrative, and structural metadata, some or all of which may be embedded in individual images.

Use Cases: Derivative Images and Image Sets

• Patron views inline image in user interface.
• Patron makes a hard copy of one or more images for personal use.
• Patron is able to see depictions of the front, back, sides, top, and bottom of the object, and several details.
• Patron is confident that the content received is an accurate and/or authentic reproduction of the original item.
• Patron (or content delivery system) receives information on rights and restrictions (delivery system may act on that information, if appropriate).
• Patron downloads one or more of the derivative images and, later, uses embedded metadata to identify the content and to determined technical and provenance information about the image.
• Patron studies, say, the surface texture of a sculpture.
• Publisher uses image to illustrate a high quality book.
• Publisher uses image to illustrate a large fine art poster.
• Publisher uses image to create museum-quality print.
• Exhibit designer uses image for display "mural."
• Broadcaster uses image in high-definition television program, possibly with a Ken Burns effect.
• Digitizing organization produces and archives an image that documents the condition of the original physical item in order to support its conservation.

Quality Notes

Inline image in user interface:

• Pictorial content is reasonably clear. Zoom in may be required.

Hard copy output:

• Equivalent to good quality photocopy.

Patron confidence in accuracy and/or authenticity:

• Depends upon provenance metadata (attribute of the copy) and trustworthiness of the provider (attribute of the institution).

Example of, say, sculptural work details for study:

• Researcher can select a variety of details from the image set and examine fine features or elements of the work.

Image used for book illustration or large poster:

• "Studio quality," permitting an accurate reproduction of the shapes, tones, and colors of the original. Good enough to make printing plate(s) for a halftone printed in color.

Image for use as an exhibition mural:

• "Studio quality," permitting an accurate reproduction of the shapes, tones, and colors of the original on a digital printer.

Image for use in high-definition television program.

• "Studio quality," permitting an accurate reproduction of the shapes, tones, and colors of the original. Good enough to fill high-definition screen and zoom in using a Ken Burns effect.

Note: Derivative images will generally be in an output-referred image state.

Recommended

Note: The 2004 NARA Guidelines also include alternate, reduced resolution specifications similar to those below. These alternate specifications are not included here.

• 10 to 16 megapixel 24-bit RGB mode image, can be produced from a 48-bit RGB file.
• If scanning photographic copies of objects and artifacts, see recommended requirements in the appropriate photo charts.