Produced by Robert W. Allison
Assoc. Prof of Religion, Bates College, Lewiston, Maine and
Research Fellow Ektaktikos of the Patriarchal Institute for Patristic Studies, Thessaloniki

© 1996 Robert W. Allison. All rights reserved.

Description of Watermark Prints in this Archive

The prints in this archive are in JPEG format. They are typically about 100-200 K in size. They were compressed at a low level of resolution (10%), which has affected only dark areas in these prints. Since the watermarks and the grid of wire and chain lines are white, they are unaffected by JPEG compression.

The process by which they were created was as follows.

  1. Initially contact prints of the watermarks were made on Dupont Dylux® proofing paper. (See Method for making contact prints for instructions on how to do it yourself.) This method produces a fully detailed print in which the watermark and the grid of wire and chain lines appear as a light yellow image against a darker blue background.

  2. These contact prints were then scanned at a resolution of 400 DPI and saved as TIFF images, only the red channel being saved. (The red channel, like a red filter in traditional photography, heightens the contrast between the light yellow tones of the watermark image and the blue of the background.)

  3. The TIFF images were in turn computer-enhanced to reduce the visual impact of the written text and further increase the contrast between the light tone of the watermark and wire/chain lines and the dark tones of the surrounding paper.
    The enhanced TIFF images will be used to generate printed facsimiles of the watermark prints from the manuscripts of Philotheou Monastery for the forthcoming Catalog of Greek Manuscripts of Philotheou Monastery, to be published by the Patriarchal Institute for Patristic Studies in Thessaloniki, Greece.

  4. Finally, these images were converted to JPEG format on the Bates College Unix server, Abacus. Since a direct conversion to JPEG was not possible, a two-step conversion was necessary The TIFF files were first converted into a format called pnm by a program called tifftopnm. Then the resulting pnm files were converted to JPEG format using a program called cjpeg. This program will take the output from tifftopnm and turn it into a jpeg, allowing you to select the compression quality. As indicated above, we found that a low quality of 10%, which allowed for maximum compression of the images, affected the resolution of detail only in the dark areas of the prints. Since the watermarks and the grid pattern of chain and wire lines appear as light areas in the paper, the compression actually aided our enhancement of the image.


    Scanning and computer enhancement of the images of watermarks in the manuscripts of Philotheou Monastery in this database were done in 1994 at the Camden Center for Creative Imaging, Camden, Maine, by Annie Higbee and were funded by a research grant from the National Endowment for the Humanities.

    The original contact prints were made at the Monastery by Robert W. Allison, assisted by two students at Bates College, Samuel Taylor and Leonidas Nicholas.

    The conversion method described above was developed by Rob Spellman of the Bates College Computing and Information Services and implemented by Robert Allison.



    Created by Robert W. Allison
    Dept. of Philosophy & Religion, Bates College
    Lewiston, Maine 04240

    Last updated October 5, 1996

    © 1996 Robert W. Allison. All rights reserved.