Re: could it be bubbles?

[jdgoff@xxxxxxxx]

At 09:19 AM 12/3/96 +0000, you wrote:
>HiYa
>
>I just got a film back from the lab and there are lots of undeveloped spots
>on the film, about 1mm in diameter.  These are clear on the negative, and
>some have a tiny developed spot in the centre.
>
>They are randomly distributed on the surface ofthe film, with some
>clustering and some frames nearly free of em.
>
>I doubt its a film thing, but waddya reckon?
>
>
>BTW ... The film is Kodak IR black and white
>
>
>Major piss off man
>---
>
>Chris Eastwood                           email c.eastwood@xxxxxxxxxxxxx
>Software Engineer                        phone (07) 3875 7599
>ITS
>Griffith University
>Queensland
>AUSTRALIA
>
>************************************************************************
>
>'But oh, beamish nephew, beware of the day,
>     If your Snark be a Boojum!  For then
>You will softly and suddenly vanish away,
>     And never be met with again!'
>
>
I don't mean to give a simplistic or obvious answer, and without seeing the
negs, I am speculating. The spots your describe seem consistant with air
bubbles trapped on the surface of the film during development. You didn't
say if your film was 4X5 or 35mm. Trapping bubbles on a roll film's surface
is not uncommon, and most instructions for use of daylight tanks suggest
that the tank be rapped briskly on the sink or counter to dislodge these
bubbles. My experience with cut film development using open, non-daylight,
tanks and film hangers is that if one raps the hanger on the tank edge after
each agitation, the bubble problem will not occur. In fact, I have had much
less problem with cut film bubbles, generally. I infer you submitted your
film to a lab of some kind. I cannot speak for your area, of course, but
when I had a studio (without darkroom) for a brief period in So. California,
many darkroom techs at that time (several years ago) were severely
inexperienced. Also, many of my students, who are darkroom beginners,
experience the bubble-on-film effect. It seems they are a little shy about
rapping their tanks. As to the density in the center of the clear area, I am
at a loss to explain without seeing them. Finally, although a rare event, it
may be that some contamination was splashed on your film, e.g., stop bath,
fixer, other chemical. Oh, by the way, my experience with Kodak HIR in 4X5
is that it is VERY sensitive to the salts on one's hand. Apparently, these
salts are able to unite with the halides within the emulsion. After much
effort to keeps hands 'clean', I have finally gone to loading/unloading this
film while wearing cotton gloves as one would do while handling color
slides. Hope this has been useful. Let me know how it turns out. Otherwise,
greetings from the SW corner of Colorado, USA---James


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Topic No. 4