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, 1999 Robert W. Allison. All rights reserved.

How to make contact prints using Dupont Dylux® Proofing Paper

The method here recommended for making watermark prints was developed by Thomas L. Gravell and employed in Gravell's publications of papers from documents in the Library of Congress. The watermark prints in this archive from the manuscripts in Philotheou Monastery were made using this method.

Capsule Description of the Method

Watermark prints are made by shining light from a blue daylight fluorescent tube through the watermark bearing paper onto a sheet of light-sensitive Dylux® proofing paper. This paper is coated with a yellow light-sensitive pigment which turns deep blue when exposed to ultra-violet light, but which is deactivated by exposure to the blue daylight. (See About Dylux Paper for a detailed description of its manufacture and chemical properties.) The light passes more quickly through the watermark and the grid of chain and wire lines, which are thin spots in the paper, than it does through the rest of the paper. The light is removed when it has had time to penetrate the thin areas, but before it has been able to penetrate the thicker areas in the paper. Where it penetrates, the blue daylight neutralizes the dyes in the Dylux® proofing paper. Thus, an image of the watermark and the grid of chain and wire lines is produced on the underlying sheet of light sensitive paper.

This image, at first invisible, is brought out by exposing the light-sensitive paper to ultra-violet light. This second exposure turns the dyes in the light sensitive paper from yellow to blue, except for the areas where the dyes were neutralized by the first exposure. Thus, the watermark now appears as a light yellow design against a darker blue background.

Finally, the image is fixed by a repeat exposure to blue daylight from a fluorescent tube, which neutralizes all remaining active dyes in the Dylux® paper. The more detailed instructions that follow are adapted from Thomas Gravell's instruction sheet, which he has circulated privately among scholars interested in making such prints. I have supplemented his instructions in places based on my own experience with this method.

Thomas Gravell's Instructions for the Dylux® Method

Dylux® 503A is a photosensitive paper made by E. I. du Pont de Nemours & Co., Inc. for use as a proofing medium in the printing industry. It comes in several types and coatings, but for use in printing watermarks Dylux® 503A is the best. The paper is coated on one side with a yellow dye. This dye is not water soluble, will not rub off and is neutral for acidity. Room light from tungsten bulbs does not affect the Dylux® paper's ability to react to the imaging fluorescent tube. Cool white fluorescent tubes will only affect Dylux® paper's reaction time after a period of several hours. The dye's low level of sensitivity to these light sources will allow Dylux® to be used in a well lighted room when working with fragile manuscripts or books. On the other hand, direct sunlight will within a few seconds begin to activate Dylux® paper's dye reaction. Since ultra-violet light causes the dye to turn blue, care must be taken to shield dylux® paper from U.V. light rays both during the process of making prints and during storage.

List of Supplies & Equipment Needed

  • Supply of Dupont Dylux® 503A proofing paper
  • a small lamp with a pair of 9-12 inch blue daylight fluorescent tubes
  • A second lamp with a black-light (u.v.) fluorescent tube.
  • Envelopes or folders in which to keep prints to prevent deterioration of the images before they can be fixed
  • sheets of glass or plexiglas of various sizes appropriate for use with books of different sizes
  • Spring paper clips and/or clothes pins to clip together the glass or plexiglass panes on either side of the watermark bearing paper (see illustration)
  • Procedure

    1. Place the Dylux® 503A on a flat smooth surface, yellow side up.

    2. Next, place the watermarked sheet of paper on top of the Dylux® paper.

    3. Position the glass plate on top of the two papers.

    4. If the paper is cockled, place a second glass plate beneath the Dylux® and clip the two glass panes together around the edges to be assured of good contact between the watermark bearing page and the Dylux® paper.

    5. Expose the page to the blue daylight fluorescent light.

    6. Remove the manuscript to a location away from the u.v. light, then wave the ultraviolet tube over the exposed Dylux® sheet. In a few seconds the Dylux® paper will turn blue, except for the watermark print and the grid of wire and chain lines, which will now appear as a yellowish-white pattern on a blue background.

    7. Fix the image by placing the Dylux® paper once more under the blue daylight fluorescent tube for several minutes, until all evidence of the yellow dye has disappeared.
    Dylux® paper is distributed by E. I. du Pont de Nemours & Co., Inc. in packages of 500 sheets measuring 8.5 x 11 inches. Since most watermarks are only 3 x 7 inches in size, two prints can be made from a single sheet of Dylux® paper.

    Cautions: While Dylux proofing papers are safe to handle, and from a paper conservaton standpoint safe for contact with papers and inks, users should be aware that an "offgas" is released by the chemicals, so that the paper should only be used in a well ventilated area, and not by users who have reason to think they might be sensitive to chemicals used in Dylux proofing paper or to chemicals in general. Users are referred for detailed information to the Materials Safety Data Sheet (MSDS) issued by the manufacturer entitled "DYLUX" OFFGASES FROM FILM OR PAPER and advised to read the information on offgases carefully. I have heard from one user of Dylux paper who reports that as a result of extended exposure to Dylux offgases in the workplace, he is no longer to tolerate most chemical exposures.

    Robert W. Allison
    Shelf life of Dylux® paper is said to be one year. If kept in a cold place, however, shelf life can be extended to two or three years. (I keep my supply of Dylux® paper in an unheated cellar, and have found that it will last three years.)

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

    Last updated September 10, 1999

    © 1999 Robert W. Allison. All rights reserved.