on 11/10/04 10:08 AM, Mary Ballard at [log in to unmask] wrote:

> Hi everyone: here's a question I just got: is it ok to scan antique textiles
> on the digital scanner? The advantages are that the image is 1:1; the front
> and back can be scanned; it's easy; it's quick. The disadvantages would seem
> to be the bright light and it's duration over a small section of a textile art
> work. At SCMRE our scanner uses a xenon gas cold cathode fluorescent lamp. It
> appears as though the peaks of the spectrum exclude ultraviolet but include
> infrared at least for one manufacturer. Certainly the glass cover would act as
> a filter, but has anyone put a light meter against one of these scanners to
> determine the footcandle or lux level that a textile would receive? Mary
>
I agree that this information would be very interesting and potentially
useful.  However, I think that the duration might outweigh many if not most
of the other variables you are considering.  I would see this as pertaining
to most "average" textile scenarios, excluding extremely sensitive
materials/dyes.

Research into light levels and exposure criteria with reference to flash
photography have proved that the duration is of great importance in these
types of discussions.  Admittedly, the scanner light duration is much
greater than that of an electronic flash.  However, as long as the textile
in question is not subjected to this light frequently I would be surprised
if the necessary activation energy levels are reached and held for
sufficient time as necessary to initiate the degradative chemical reactions
within the fabric and dye stuff.

I look forward to seeing whatever else is posted concerning this question.

Note:  Newer scanners with Firewire connections are often much faster in
scanning and pushing the information through to the computer, resulting in a
shorter exposure time for any given area of the textile.  Therefore, when
possible using a newer, faster scanner is potentially less damaging.


Mark MacKenzie, M.A.C.
Conservator, Western Development Museum
Sasktoon, Saskatchewan
Canada