Policies and Guidelines
Parks Canada Archaeological Recording Manual: Excavations and Surveys
APPENDIX H: Digital Multimedia – Recommendations for Preservation
The following recommendations are based on Parks Canada (2003a) “Report to Parks Canada: Digital Multimedia Asset Management (DMAM) System Policy Requirements Version 2.0.” Digital preservation is still in its infancy. As a result, it is difficult to determine which format is the best for long term preservation of digital assets. Despite these obstacles, Parks Canada (2003a) currently recommends the following guidelines. Due to the dynamic nature of digital media, please consult the appropriate specialists to determine latest trends and standards adopted by the Parks Canada Agency.
Preservation Formats for Images, Audio, and Video (General)
For preservation formats, Parks Canada generally recommends:
- Images - high resolution TIFF 8 x10 at 600dpi;
- Audio -WAV format or MPEG 2 format;
- Video - MPEG 2, 4:2:2 compression standard. The MPEG 2 format that has been an ISO standard since 1996.
Image Formats for Storage/Preservation
As noted in Parks Canada (2003a), the Image Quality Working Group of ArchivesCom (associated with Columbia University) recommends the following image formats for preservation storage purposes:
- TIFF w/CCITT Fax 4 Compression - ideally suited for black and white text documents, this format provides a high level of detail (600 dpi), combined with a small file size (less than 100 kilobytes for 5"x8" text page);
- PhotoCD - well suited for 35 mm slide and 35 mm negatives, PhotoCD provides up to 6 resolutions (up to 4096x6144), colour management, and a storage medium that works on all major computer platforms;
- TIFF w/LZW Compression - A 24-bit, lossless (no information lost) compression format. This TIFF format may be used to store colour images, and may be used as preservation file format. With lossless compression, the picture quality of the compressed file is exactly the same as the original, uncompressed file.
Different original media types will require different digital conversion techniques as well as different file storage formats. This is an area that is evolving, as both conversion techniques improve (better scanners and digital cameras) and new file formats develop.
Multimedia File Format Recommendations
Table 1, copied verbatim from Parks Canada (2003a), represents a set of recommendations for a variety of media, derived from the United States National Digital Library.
Table 1. Parks Canada recommendations for digital multimedia.
|Media Type||Conversion Method||Resolution||Archive File Format||Screen Presentation Format||Print Presentation Format|
|Black & White Text Document||Flatbed Scanner or Digital Camera||1-bit, 600 dpi||TIFF w/CCITT Fax 4 Compression||GIF, 4-bit, 120 to 200 dpi||Acrobat (PDF), 1bit, 300 or 600 dpi|
|Illustrations, Maps, Manuscripts, etc.||Flatbed Scanner or Digital Camera||8-bit greyscale or 24-bit color, 200 to 300 dpi||TIFF||Multiple JPEG, 24-bit, 512x768, 1024x1536, 2048x3072, Quality Level 50||JPEG, 24-bit, 2048x3072, Quality Level 50-100|
|3-dimensional objects to be represented in two-dimensions||Digital Camera||24-bit colour, 200 to 300 dpi||TIFF||Multiple JPEG, 24-bit, 512x768, 1024x1536, 2048x3072, Quality Level 50||JPEG, 24-bit, 2048x3072, Quality Level 50-100|
|35 mm Black & White & Colour slide or negative||PhotoCD or Slide Scanner||24-bit, 2048x3072||PhotoCD or TIFF||Multiple JPEG, 24-bit, 512x768, 1024x1536, 2048x3072, Quality Level 50||JPEG, 24-bit, 2048x3072, Quality Level 50-100|
|Medium to Large Format photograph, slide, negative, transparency or colour microfiche||ProPhotoCD or Drum Scanner||24-bit, 4096x6144||PhotoCD or TIFF||Multiple JPEG, 24-bit, Quality Level 50||JPEG, 24-bit, 4096x6144, Quality Level 50-100|
|Black & White Microfilm||Microfilm Scanner||1-bit 600 dpi
8-bit, 300 dpi
|TIFF w/ Fax 4
|GIF, 4-bit, 120 to 200 dpi
GIF, 8-bit 120 to 200 dpi
|PDF, 1-bit, 300 or 600 dpi
PDF, 8-bit, 300 or 600 dpi