Re: Newton Rings

Judy Seigel (jseigel@panix.com)
Tue, 27 Jun 1995 21:51:49 -0400 (EDT)

On Thu, 22 Jun 1995, Carson Graves x4692 3NE wrote:

> > I put layer of "finest talc" baby powder
> > in bottom, and practiced shaking it, counting to 3, and then going
> ^^^^^^^^^^^^^>
> Just a slight correction. You should wait at least 30 seconds to make sure
> that only the smallest particles are in suspension. So, unless you count
> much slower than I, you might want to just time the 30 seconds (or
> longer) with your watch.> > Good luck,> Carson

Well, hello again list! I missed you -- and of course missed the slight
correction from Carson, since my modem was in killer mode when it arrived.

Another message I also didn't get was from Sam Wang -- who said he
hated to spoil the fun, but a product called Geramn Tetenal anti-Newton
Spray available at my photo-supplier would solve the problem perfectly.

Lacking either message I learned by doing. Waited 5 seconds (adding 2 for
good measure!), sprayed, saw no Newton rings at pressure, scented victory,
made positive, looked with lupe & .... heartbreak -- MANY white specks,
clouds of them!, caused by opaque clumps of talc. Need I describe the
negative cleaning process? (Actually, re-washing worked fine.)

Next I tried cornstarch. Perhaps my talc was gummy, or maybe I'd just
learned greater circumspection -- though the cornstarch, unlike the talc,
wiped off easily when I overdid it. Anyway, I waited longer,kept dispenser
nearly vertical, held neg at arm's length and just waved it through the
barest detectable mist. Got contact positive with no Newton rings, no talc
spots!! (Thank you, Carson.)

Victory? Hurrah? In a sense yes, and certainly intimations of the
despair/triumph Newton-Ring cycle, BUT, the main lesson I learned was
how dumb I was. So, in the unlikely case that anyone else plans to be
equally dumb: DON'T! Don't try to make a contact positive from a 35 mm neg
unless you have a state-of-the-art clean room. (Some of you do have such
dust & debris-free spaces, I gather. I never thought my darkroom was THAT
dirty -- but I found a thousand of everything on the frame and could NOT
get it off, my most tender delicate ministrations with brush & air leading
only to ugly patina of surface scratches.)

All of which leads up to the fact that another benefit of making the positive
full-size (besides having a positive for variations in gum) is the
relative ease of retouching. My squiggles & blobs, being clear in the
positive, will print black on the negative, where I'll have to bleach
them out (MUCH more trouble than retouching) or retouch each print.

Fortunately, as I mentioned in my last, the large film positive
that I contacted to film in the same vacuum frame, though it showed Newton
rings to the eye, did NOT print them on the film. (All 35mm negs tested
printed the Newton rings.)

Anyway, thanks to all. Happy to be here. Happy to provide so much innocent
amusement!

Judy