[LargeFormat] A better way

[Karl Wolz]

Man - you learned a lot!  With a bit of time, you'll be able to sort it
out and unlearn half of it ;-)

JOBO print development takes place in a simple cylinder - the paper back
hardly gets wet.  Film has what's called an anti-halation layer on the
back side (keeps light from bouncing around inside the film and causing
"halos" around highlights).  This layer needs to be dissolved and
removed during development, so film must be held in a position such that
chemistry can circulate around it.  You actually can develop film in
print drums, but you'll most likely have to rewash the film after
processing - too much chance of damage for my tastes.

The CPP is physically large enough to process an 11x14 print, but JOBO
doesn't make a drum to hold anything larger than 4x5 for that unit (drum
diameter is the limiting factor here).  The PRO drum looks kinda like
the bullet holder in a revolver, where each piece of film sits in its
own chamber.  This unit is about ten inches in diameter, hence the need
for a larger processor.   The large diameter is the reason that JOBO
suggests the use of an air pump to lift the lid - it's hard to get much
leverage with your thumbs, though it apparently can be done.

Good luck,

Karl Wolz

> -----Original Message-----
> From: largeformat-admin@f32.net [mailto:largeformat-admin@f32.net] On
Behalf
> Of Hornford, Dave
> Sent: Wednesday, August 07, 2002 8:07 PM
> To: largeformat@f32.net
> Subject: RE: [LargeFormat] A better way
> 
> If I may summarise what I have learnt today:
> 
> Without question the ATL-2400 is my best choice. To take full
advantage
> I will have to increase my Provia use from 8-16 sheets per month to a
> larger number.
> 
> Both the CPE & CPA have happy productive owners who would heartily
> recommend them (although with far more reserve than Jim's
recommendation
> of the ATL-2400). A careful user of either should be able to produce
> high quality work with either, despite JOBO's dark hints about
> perfection & complete randomness with an expert drum - an engineer
> friend who works on turbine design on pipelines will only chuckle to
> himself when asked about randomness & flow patterns in constricted
> turning spaces (I told him the job designing mountain bikes would be
way
> better - think about the people looking for a deal turbine for a
96inch
> pipeline compared to buddies who want to upgrade their bikes or
> volunteer as test riders?)
> 
> Both the CPE & CPA can happily process a normal run of 8 slides
> (CPE/2553 drum/pair of reels does 8 sheets of 4x5 or CPA/expert drum
> provides 10 sheets)
> 
> In terms of differences:
> The CPA/expert drum combination either requires the careful use of
> towels & vaseline or a bomb disposal technician and pump (I am
beginning
> to understand a few more references in Uncle Dick's posts)
> The CPE is limited to 600ml of liquid vs 1,000ml for the CPA; and the
> CPE is a smaller beast. The liquid limitation impacts the use of
> dilutions for roll film more than sheet film, but still significant
for
> those of us who can't get over the lack of Pan F sheet film.
> 
> Outstanding question:
> How can a CPE do 11x14 prints but not 5x7 sheet film? Can one use a
> print drum for sheet film?
> 
> 
> Thanks,
> Dave
> 
> 
> Dave Hornford
> "Once in a while you will stumble upon the truth but most of us manage
> to pick ourselves up and hurry along as if nothing had happened."
>     --- Winston Churchill
> 
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