Still Photo Median - 3000 Line [SPF-R1]
|Record Type||Still Photographs - Film Negatives and Positives|
|Expected Use||Reproduction Master|
|Product Name||Still Photo Median - 3000 Line [SPF-R1]|
The purpose of this product is to respond to reference and reproduction requests.
|Nature of Source Material||
|File Properties||Data Format||
TIFF, version 6.0 (.tif)
The image is always presented as a positive image regardless of its original polarity.
Typical file size:
For 24-bit color: ~20.6 MB
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.
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.
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
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.