On Wed, 26 Feb 1997, Sil Horwitz wrote:
<snip>
> As another point: the "Estar" base films use polyester film; these could
> also be a problem with processes requiring UV exposure. I haven't done any
> testing in this area, but it's a good one to place in my backlog. Has
> anyone experimented in this field? If so, let me know, as it would help in
> providing a starting point.
>
Finally I'am able to contribute some hard data myself..;-).. I did some
testing last week with different (clear) film base. I used a
spectrophotmeter for it, and measured the spectrum from 200 to 400 nm
(basicly I took a small "strip" of clear film base, put it in an crystal
cuvette (small chamber)and measure the absorbance (density) by different
wavelengths)
Since I use Xray film for enlarging my 6*6 negs I was most curious about
that, this film (Konica A2, blue base), shows considerable blocking of UV
upto 360 nm (since I use a scientific UV light bank at 312 nm, I have to
change to higher UV wavelengths to reduce my printing times
(20-30 min, Cyanotype contactprinted).
I also tested the Polaroid neg of Polaroid P/N material (btw. tested it
for cyanotype, when exposed at 25 ASA, works quite nice, so I guess that
Pt/Pd is also possible, answering my own question about that some time
ago) This material also shows blocking upto about 360 nm
Finally I tested Afgapan APX 100, this neg. material shows blocking upto
320 nm
Hope this info is of some interest, I could test some other films as
well...
Cor Breukel
http://ruly70.medfac.leidenuniv.nl/~cor/cor.html
"The Infrared Gallery"
http://ruly70.medfac.leidenuniv.nl/~cor/ir-gallery.html