Digitization

Digitization is a crucial aspect of collections care at the Smithsonian Institution Archives. The Archives adheres to international standards and best practices for digitization, for instance the Federal Digitization Guidelines Initiative, and produces high quality archival images, audio, and video useful for researchers, scholars, and the public. Digitization protects original historical documents and analog records from further deterioration and damage because it eliminates repetitive handling.

The Archives employs procedures and specifications to minimize the number of times a collection item undergoes digitization for access or preservation purposes. Other specialized techniques, such as spectral imaging, are used when performing diagnostic digitization as part of a conservation treatment.

Digitization Standards for Still Images

Resolution

  • 6,000 pixels on the long axis of the image (600 pixels per inch (ppi) for an image 10 inches long)
  • Minimum value is 600 ppi, increasing resolution in intervals of 25 ppi as necessary to achieve a minimum of 6,000 pixels along the long axis

Digital File Format

  • Tagged Image File Format (TIFF) using Windows (PC) byte orientation.
  • For color images, a 24 bit RGB setting is used, yielding 8 bits per color channel.
  • For black and white images, a 24 bit RGB setting is used. Note: for images from microfilm, a resolution of 300 ppi grayscale is acceptable.

File Compression

  • None

Metadata Standards

The Archives collects and maintains cataloguing data as part of its collections management system.  From this data, selected elements (metadata) are embedded in the digitized content using the best practice guidelines developed by the Smithsonian Embedded Metadata Working Group. The elements use fields from the International Press Telecommunications Council (IPTC) Core standard. Mandatory embedded elements are; Document Title, Copyright Notice, Source, and Creator.