The purpose of this product is to respond to reference and reproduction requests.

• Hard copy source images still print in any size not at risk due to deterioration or obsolescence
• Any still print still image digital preservation master file in any size

TIFF, version 6.0 (.tif)
Uncompressed

Bit Depth

• 8-bit grayscale for B&W
• 24-bit RGB for monochrome and color

Pixel Array

• 3000 pixels across the long dimension

Spatial Resolution

• Calculate from actual image dimensions
  • Approximately 2100 ppi for 35mm originals and ranging down to the appropriate resolution to produce the desired size from larger originals
  • Approximately 600 ppi for 4" x 5"
  • Approximately 300 ppi for 8" x 10"

Dimensions

• Match original size; no magnification/reduction

Typical file size: For 8-bit grayscale: ~ 6.8 MB
For 24-bit color: ~ 20.6 MB

• Recommended level specified in NARA's 2004 Technical Guidelines

Although the NARA 2004 Technical Guidelines and the FADGI 2010 Technical Guidelines suggest scanning at 2700 x 2700 for square formats, the Photographic Imaging, Microfilm and Textual Preservation Lab does not differentiate between square and rectangular formats and follows a 3000 line approach for both.

The Digitization Services Branch’s Quality Assurance and Quality Control (QA/QA) program is evolving as new tools and resources are acquired and implemented. We are moving towards more automated and integrated systems to assure the products we make meet the specifications outlined. Digital products created by the Digitization Services Branch are validated against standardized format specifications and signature files when possible. We use a variety of format specific batch evaluation and validation tools both open source and vendor supplied, to assure technical quality level specifications are met. All files, but especially distribution system specific files, are inspected for successful playback in a variety of tools and environments. Additional quality control workflows are in development.

Equipment/System Evaluation
NARA implements scheduled service and calibration protocols according to manufacturer recommendations as well as on an "as needed" basis.

Metadata
Embedded metadata: NARA is working on embedded metadata guidelines for all file types.
Technical metadata: NARA is finalizing technical metadata schemas for all file types.

NARA is developing an in house job tracking order system to better coordinate work at the Branch level.

Item Level Evaluation: Automated File Characteristics Analysis
Fixity: NARA is evaluating workflows to create and validate checksums for each digital file.

For additional QC protocols for products created on the Zeutschel Camera System, please see Quality Assurance and Quality Control for Digital Products Created on the Zeutschel Camera Systems

The Photographic Imaging, Microfilm and Textual Preservation Lab uses the uncompressed TIF file format for preservation master files for all the record types it processes. Currently, NARA does not use JPEG 2000 or other means of compression in preservation master files, including LZW compression within TIF files.

Reproduction master files can be either uncompressed TIF or JPG if compression is required.