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Imaging

Parker manuscript images were created by Cambridge University Library imaging staff, working in dedicated space at Corpus Christi College:

  • Using state-of-the-art digital capture technology
    • 3 custom-built rigs with cradles
    • 2 Linhof Master Technika 2000 4 x 5 cameras and 2 Anagramm PictureGate Salvadore digital backs (8000 x 9700 pixels, producing an average file size of 222 MB)
    • 1 Hasselblad camera and a PhaseOne P45 digital back (7230 x 5428 pixels, producing an average file size of 120 MB)
    • 120 mm lenses used for most work; 135 mm lens for special items
  • With imaging workflow supported by Capture One software
  • Using a color-managed process, baseline RGB/DLF Benchmark for Faithful Digital Reproductions of Monographs and Serials: color
  • Saving master files in uncompressed TIFF 6.0 format for preservation archiving
  • Produced in an environment that was safe and protective of each manuscript
  • Validated by stringent quality assurance procedures at each stage

Master image files were delivered to the team at Stanford University Libraries, where they underwent additional quality checks, image processing, and preservation archiving in the Stanford Digital Repository. Sub-masters and derivative images were produced by the Stanford team as follows:

  • Two sub-masters were created for each master image file, both LZW-compressed. Color correction, deskew, and rotation were applied as necessary. One sub-master remained uncropped to include a color bar and scale. The second sub-master received identical rotation, color correction, and deskew, and the color bar was cropped to present the images with minimal visible background.
  • A JPEG2000 derivative was produced for each sub-master. JPEG2000 files were encoded using the Aware codec at a PSNR of 46.
  • The average size for each 5-file set (1 master, 2 sub-masters, 2 derivatives) was 500 MB for the Anagramm-produced images and 400 MB for the P45-produced images.