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Subject: Image enhancement

Image enhancement

From: Tom Vanderlinden <tomv>
Date: Monday, November 29, 2004
Leslie Courtois <conlab [at] lva__lib__va__us> writes

>I have two non-conservation colleagues who are trying to enhance the
>image of mechanically abraded "faded" iron gall ink on parchment.
>They are imaging at very high resolution (800 ppi at 48-bit) using a
>BetterLight scanning back, a 120mm Schneider Apo-Symmar lens, with
>full spectrum fluorescent lights.

We have had success with a simple "black light" (a fluorescent tube
producing nearly only ultraviolet light, available in novelty shops
for less than $20 US) in photographically capturing writing from a
mid-1700's parchment notebook cover. The writing in this case was so
hidden in normal light, it's presence had gone completely unnoticed.
After digital photography under this ultraviolet light source, (with
no other source of light) and then manipulation of the image in
Photoshop, nearly all of the writing was able to be transcribed, and
found to be words of the man who, on the interior pages, had
recorded his field experiences as a pre-American Revolutionary War
soldier, gunsmith and engineer.

Tom Vanderlinden
Printing for preservation
Bridgeport National Bindery

                  Conservation DistList Instance 18:25
                Distributed: Wednesday, December 1, 2004
                       Message Id: cdl-18-25-011
Received on Monday, 29 November, 2004

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