Re: Lith film

From: Liam Lawless <liam.lawless@blueyonder.co.uk>
Subject: RE: Lith film
Date: Fri, 12 Dec 2003 15:55:46 +0000

> Freestyle couldn't offer any explanation, so I finally put it down to
> X-ray damage.

I'd think that's unlikely unless you have a clear evidence that the
film was clearly x-rayed, such as uneven fogging, shadows, etc. Also,
x-ray exposure is not capable of making fine texture on affected
film... they only leave big, fuzzy features. Your description said
oyster shell markings, which I think is too fine a texture to
attribute to x-ray.

If you want to test if the material has been affected by x-ray, you
can order one roll of Tri-X or HP5 Plus, which is more sensitive to
x-ray than lith films, and develop them... if Tri-X isn't affected,
lith film is safe.

Although all silver halide materials are sensitive to x-ray exposure
to a verying degree, films that are particularly sensitive to x-ray
are those with large crystalline sizes with use of heavy metal dopants
to enhance x-ray absorption. (X-ray films are made that way, usually
doped with lead, and thickly coated on both sides of the support.)
Lith films don't use dopants or co-precipitating metals that
particularly enhance x-ray absorption (lith film dopants may even
sacrifice sensitivity), and lith film crystals are way too small to
get enough x-ray sensitivity. That is, most x-ray would just go
through the material and wouldn't fog the material... unless very
strong dose was used, in that case you should see some overall fogging.

--
Ryuji Suzuki
"Reality has always had too many heads." (Bob Dylan, Cold Irons Bound, 1997)