Re: [APML] Hypering fog

[George Anderson <georgea@cam.org>]

Hi Don

Thanks again for the sage advice and warning (and the same to others who
have offered advice to this hypering newbie). I was thinking about
taking a clip off of the films when they come out of the chamber and
developing them to look for fog before I bothered with shooting them.
So if the skies stay clear tuesday night I'll shoot the two experimental
films rather than the tech pan (even though I want to try the TP) and
develope them tuesday night. I probably won't be able to scan until
wednesday but I will give a verbal of the eyeball evaluation when I hang
them up to dry.
If they do show promise but end up too dark I'll try the incremental
route to get a rough number of where to start. If I have anything
worthwhile I'll get your address and pop some samples down to you for
real testing.

George

Cler skies and good health

Don Westergren wrote:
> 
> George,
> 
> Since not all films respond to hypering with a density change,  you will
> probably have to evaluate the test film exposures that are clear to see if
> they changed by being hypered.  Of all the film hypering recipes I've seen,
> TechPan takes the longest.  If your test films show a density change, you
> will probably have to go the guesstimate route, try 25% time and adjust to
> 12.5% or 50% depending on the outcome.
> 
> Another way to try hypering an unknown film is to hyper a roll for say 5 or
> 10 hours, expose and process a frame or two, then rehyper the rest of the
> roll for another 10 hours if warranted.  You can repeat several time
> increments to help narrow in on a hypering recipe.  Incremental hypering is
> not as precise as hypering in one shot, but can help conserve film and time.
> Remember every time you take a film out of the hypering chamber, it will be
> exposed to ambient oxygen and moisture so you want to put the unexposed film
> back in your vacuum chamber while processing a test exposure piece of film.
> 
> We are all anxious to hear about your results.
> 
> Don
> 
> > Since I am attempting to hyper two unknown films as well as some TP (all
> > at 100 hours) I have a question obout guesstemating the correct time
> > from the amount of fog.
> > Assuming that I am lucky and one or both of the other films responds and
> > the background fog is substantially higher, is there a rough rule of
> > thumb to put me in the ballpark or do I just try 25%, 50% and 75% of the
> > hypering time and narrow it down from there?
> >
> > George Anderson
> > Montreal Canada
> >
> > Clear skies and good health
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> >
> >
> 
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