| Basic description
|| Photographic negatives and prints dating from 1890-1940. Multiple source formats:
- Nitrate acetate
- Prints (various types)
Each format digitised by a separate supplier over the course of 18 months. In theory all the prints were made from a negative which was also digitised, but not necessarily.
High-res digital images should conform to one of two specifications:
- Master - TIFF, 48-bit colour, Adobe 1998, 1200ppi - unaltered from scanner
- Post-processed - TIFF, 24-bit colour, Adobe 1998, 1200ppi - colour level adjusted
Prints will have only post-processed files.
All negatives will have master and post-processed files.
Low-res access images will be created from the post-processed files: JPEG, 400px fixed width
|| Low-res versions will be open-access. High-res images will not be available publicly.
|| London School of Economics
| Collection expert
|| Ed Fay
| List of issues
- Consistency through time - within each format, did the supplier apply processes consistently, conform to the specification? Is there variation in the outputs - contrast, colour levels, etc - is it possible to identify where these are the result of post-processing rather than inconsistency in the originals?
- Consistency across suppliers - did all suppliers conform to the colour space, bit-depth, resolution, etc specifications
- Metadata consistency - do all digital images contain accurate metadata in the file headers and are fields populated consistently?
- Digitised negatives should come in two versions (master and post-processed) - are all post-processed files present? Is it possible to identify consistency of the post-processing (were they all subject to the same processes, do outputs conform to the intention of the post-processing - adjusted colour levels, crop to image edge)?
- Finally, is it possible to identify which of the following cases apply to each image: print with a source negative and vice versa; negative without a corresponding print; print without a corresponding negative?