Preservation

Standard Distribution Image [IMG-D1]

Record Type
Expected Use Distribution Copy
Product Name Standard Distribution Image [IMG-D1]
Product Purpose

The purpose of these files is to respond to reference requests for files with targets and other non-essential data removed for better visual presentation.

Nature of Source Material
  • Any digital preservation or reproduction master file or,
  • Any textual or photographic source object
File Properties Data Format

Depending on project needs, the follow file formats are options:

  • TIFF, version 6.0 (.tif), uncompressed
  • JPEG
  • PDF
  • BMP
  • Additional file formats may vary by locations.
Capture Information

All files:

  • Polarity: The image is always presented as a positive image regardless of its original polarity.
  • Image adjustment: Color and tone reproduction has been adjusted for generic monitor display. System calibration and/or image processing has been performed to ensure a Federal Agency Digitization Guideline Initiative (FADGI) image quality rating of at least 1-star in all categories.

If derived from a preservation or reproduction master file:

  • Same capture specifications as preservation or reproduction master file.

If captured directly from source object:

  • Resolution: Minimum resolution: 400 ppi at original document size or 4000 pixels on the long dimension for film scans
  • Bit depth: 1 bit for B&W, 8 bits for grayscale, and 24 bit for color
  • Color options: B&W, grayscale, color
  • Size: All NARA locations offering Enhanced Scan services will be able to scan objects up to 8.5" x 14". Other sizes will vary by location. Originals larger than 34" x 55" may be less than 400 ppi.

Typical file size (8.5" x 11"): ~ 43 MB

Other Information

When captured at 4000 lines or higher, this product satisfies the NARA Enhanced Scan option on the NARA Reproduction Fee Schedule.

The image does not contain targets and other references.

Quality Control Quality Assurance and Quality Control for Digital Imaging Products

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.

Customer Level Evaluation / Order Completeness

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.

Rationale

Currently, the digital distribution copy options are generally the same for all still images regardless of the format of the original source material.

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