[pure-silver] Re: how did these scratches happen?
- From: "Nicholas O. Lindan" <nolindan@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Tue, 4 Mar 2008 10:41:08 -0500
"Shannon Stoney" <shannonstoney@xxxxxxxxxxxxxxx>
[pure-silver] how did these scratches happen?
http://www.flickr.com/photos/shannonstoney/
White scratches happen because either the emulsion was distressed
before developing or the back of the film was scratched. All
the marks are parallel and the squiggles track so the chances
are the scratches were made by being scraped over an edge.
The black bits, though, are confusing - they look like tiny
gouges made in the emulsion by, say, the emulsion being pressed
against sand particles.
It is possible the film was damaged when being made. If this
is the only occurrence then I wouldn't worry too much about it
until/if it happens again. Tracking down a one-time fluke isn't
rewarding.
Questions:
1) What brand & type of film?
2) Is this the only frame with the marks?
3) Have you had the marks before?
4) On what side of the negative do you see the scratches?
5) What do the little gouges look like under a magnifying
glass?
6) The marks are on the negatives, right? Not just the print?
7) Is this a scan of the negative or the print?
The marks are not due to processing and are not
photoflow/drying marks.
Marks from film dried without/too little photoflow and/or
hard water look like white puddles, rivers, shorelines
and tear-drops. Bacterial growth in photoflow produces
smudgy stringy marks.
If you are getting streaks with photoflow the reasons are most
likely: using tap water (water softeners or Brita filters will
just make things worse); using old _diluted_ photoflow; not letting
the film sit in the photoflow long enough to let it enter the
emulsion; wiping the film down with something dirty.
Photoflow stock solution does not go off, however working strength
photoflow will support microbe growth - it can be seen as a white
slimy cloud. I dilute PF 1:20 with 91% isopropyl alcohol - pour
~3/4 oz (25 ml) into a pint (500 ml) bottle of drugstore alcohol and
mark the bottle with a Sharpie. I then dilute this 1:10 with
distilled water just before use as the final rinse.
I let the film soak in the rinse for about a minute with light
agitation/swirling. Most people let the film drain naturally - I
dip two fingers into the photoflow and use them to lightly squeegee
the film.
==
Nicholas O. Lindan
Cleveland Engineering Design, LLC
www.darkroomautomation.com
Cleveland, Ohio 44121
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