As a minimum, the UCSC Library Digital Initiatives department scans materials according to the Technical Guidelines for Digitizing Cultural Heritage Materials: Creation of Raster Image Master Files from the Federal Agencies Digitization Initiative (FADGI) - Still Image Working Group.
Master files are nearly always TIFF files with 24-bit RGB mode bit depth. Scanning resolution varies depending on the size of the original photograph or image.
- 35mm slides, negatives, and images smaller than 4"x5" are scanned at 4000 pixels across long dimension of image area, excluding mounts and borders. This results in a resolution of 800 ppi - 2800 ppi.
- Original format images in the size range of 4"x5"-8”x10” are scanned at 6000 pixels across long dimension of image area. This results in a resolution of 600 ppi-1200 ppi.
- Images 8”x10” and larger are scanned at 8000 pixels across long dimension. This results in in a resolution of 400 ppi - 800 ppi.
See page 60 in the Technical Guidelines for more details.
What do these standards mean to those of us who'd like to enlarge and print a digital file? Using this handy page that helps calculate printed images sizes based on dpi and the screen or printer resolution, here are some general guidelines:
- Images from scanned slides can generally be printed as large as 12"x18" at 300dpi.
- Images from 4"x6" photographs will print as large as 9"x14" at 300dpi.
- Images from 7"x9" photos will print as large as 21"x16" at 300dpi.
- A 14"x22" poster will print at the same dimensions at 300dpi.
Note that reproduction prints from negatives and slides are generally much better quality. For more information about printing resolutions, consult your publisher, printer or production artist.
Questions about our digitization? Send us an email.