> 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).
>
Cor, do I understand correctly that you have a machine by which you can
DIAL IN the wavelength, like dialing a radio????.... Would you like to
have the next "Meeting of the List" at your laboratory?
It isn't clear to me, however, whether that 20-30 min. for cyanotype is
the reduced printing time, or the 312nm printing time. Our school
printing time averages around 10 minutes for regular blacklight bulbs,
mine at home is usually less, so that sounds long -- though maybe there
are other structural factors.
But that's not why I'm writing -- have you described your procedure in
enlarging to the Xray film, and I just missed it? If not, would you fill
in some details about which kind of film (just had a chest X-ray, film
as big as the New York Times, mammograms only as big as Readers Digest),
about how long your exposures are, and how you develop? And what does that
film cost? (Or are you getting freeby outdated film at the lab?) Thanks!
And here's an afterthought -- is there any way this ingenious device
can be persuaded to read the sensitivity points of emulsions?
Thanks again,
Judy