Describing Image Files: The Need for a Technical Standard

Coalition for Networked Information

Fall Meeting

Orlando, Florida

November 30, 1994

Howard Besser and Jennifer Trant

---

Major Questions

• What information should be recorded about digital image files?

• Where should image files be documented? What information must be placed in the image header, and what can be placed in an accompanying text record?

• What controlled vocabularies exist to record this information? Have fields been identified to store it?

• Where can we use existing standards? Adapt existing standards to our needs? Work with other bodies to ensure the standards they adopt will meet our needs? Set the standards ourselves?

General Kinds of Information Needed

Information to view the image

• type (bitmapped, vector, video)

• format (TIFF, GIF, JFIF, PICT, PCD, Photoshop, EPS, CGM, TGA ...)

• compression (JPEG, LZW, QuickTime)

• dimensions and dynamic range

• CLUT

• Color metric (CMYK, RGB ...)

Information about the quality and veracity of the image

• source image digitized

• the source of that image (recursively>

• source type

• source ID

• institution responsible for creation of the digital image

Information about the scanning process

• light source (full-spectrum, infrared ...)

• resolution

• dynamic range

• type of scanner (for color re-balance)

• date of scan

• scanning personnel (in-house information)

• a journal/audit trail of what is done to each image and when it was done (crop, color, adjust)

• digital signatures, authentication ...

Description of depiction/surrogate

• VRA Data Standard and terminology for perspective, position, orientation, aspect ...

• linking between various views of the same original

Description of original object

• AITF Categories for the Description of Works of Art

• Systematics

• AACR2

• Other content standards ...

Rights and Reproduction Information

• copyright of original, digital copyright, surrogate copyright

• name of rightsholder

• use restrictions (viewing, printing, reproducing ...)

Location Information

• URNs, URLs, URCs

• different versions (browse, high-resolution, medium resolution) derived from the same scan