Re: [APML] Hypering LE400 in Lumicon 300?

[Philip Perkins <philip@astrocruise.com>]

Steve,

Personally I use around 7 hours for PJ400 (LE400) but you'll not go wrong 
with the 6 hours that Bobby suggested and I would recommend that as the 
best starting point.  The main thing is to test it yourself based on the 
density delta because all set-ups seem to produce a different result when 
using 50C (I have a theory that the differences between set-ups would be 
greatly reduced when using lower temperatures such as 40C or better still, 
30C).  It is most important to keep temperature under tight control and to 
keep it consistent between batches because this has a dramatic effect on 
results (far more so than any other single factor, in my experience).

I have found that pressure makes no difference at all (provided that it is 
+3psi or greater).  Nowdays I use a high pressure of +20psi in the hope 
that it produces more even results.  It certainly doesn't do any harm, and 
may be important when hypering roll film (when still rolled up!) to ensure 
that the gas permeates evenly through the layers.

Rest assured that half an hour either way will not kill the film, even at 
50C - you would need to be off target by 2 hours or more before the film 
was really "killed" :-)  But to get best results it is good to be within 
half an hour of optimum time.

You may find some inspiration on the topic of measuring density here:
http://www.astrocruise.com/densmeas.htm

It is an old article and there is much more useful info that I could put in 
there now, given a bit more time.

--Philip


At 06:02 04/08/02 -0500, you wrote:
>Here's my specs for LE400 Steve:
>6 hours at 50 deg C and 3 PSI.
>Bobby Middleton
>
>
>----- Original Message -----
>From: "steve banbury" <banburys@sonic.net>
>To: <astro-photo@seds.org>
>Sent: Sunday, August 04, 2002 12:59 AM
>Subject: [APML] Hypering LE400 in Lumicon 300?
>
>
> > I'm hypering my very first batch of 4 rolls of film tonight, and have
>gotten some pointers from Don Westergren.
> > I'd love to hear any advice anyone else cares to share about length of
>time I should hyper for.
> > I am running + 3 psi Lumicon gas, Lumicon 300 kit, and a measured temp of
>47 deg C on the Lumicon 50 deg C thermostat.
> > I have been cooking for 4 hours now, and need to decide when to quit.
> >
> > I have seen numbers ranging from 6 to 7 hours on various websites. Will a
>half an hour one way or the other "kill" the film?
> >
> > Any and all advice would be appreciated.
> >
> > Thanks--Steve
> >


Philip Perkins - philip@astrocruise.com
Wiltshire UK & Luberon France
Astrocruise - http://www.astrocruise.com


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