[LargeFormat] A better way

[Pete Caluori]

From: "Hornford, Dave" <Dave.Hornford@hp.com>
Date: Wed, 7 Aug 2002 23:07:17 -0400

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


Hi Dave,

Essentially you have the idea, but let me add a bit more.  I've never used 
the ALT processors, but I have looked at them, essentially they do the same 
thing as the CPE, CPA & CPP only they're automated.  With the CP series, you 
have to pour the chemicals in and out and time each step manually.  The ALT 
processor series automates those functions.  They are programmed for the 
various processes, so you load the drum, fill the bottles with chemistry and 
push a button, the processor does the rest.  That automation comes at a 
price.  For the volume of film you're running I doubt you can justify it.  
Since the ALT series of processors use the same drums as the CP series any 
issues with laminar flow, etc. still exist.

The CPA & CPP are essentially the same processor (they are the same size) 
but the CPP boasts tighter temperature contols and comes with a digital temp 
readout.  The CPA uses a thermometer placed in the water bath.  You can 
check Jobo's WEB site, but if memory serves me, the CPP has +/- 0.1 degree 
accuracy while the CPA has +/- 0.25 degree accuracy.  A friend has the CPA 
and processes lots of E-6, he's never mentioned any problems, nor have I 
seen any problems with his trannies.

All of the lids pressure fit on the drums, so removing them can be 
difficult, but the pump makes it easy.  To each their own, but for the few 
bucks that a pump costs, I wouldn't mess with vaseline and the potential for 
contamination.  A couple of presses of the pump and the lid pops off.

There are major differences between print drums and film drums.  While film 
can be developed in a print drum, the potential exists for uneven 
development.  There are many ribs in a print drum, that allow for different 
sizes of paper and these can create weird flow paterns as the drum turns 
causing uneven development.  Before others chime in saying they process film 
in print drums and it works, I said potential for problems; I too have 
developed film in print drums with great results.  Even if you could get 5x7 
film to stay between the ridges of an 11x14 print drum, there's no guarantee 
that they'll stay that way as fliud rotates and pours in and out of the 
drum.

As for chemistry, I've used Kodak E-6, Tetnal E-6 3-bath and 6-bath.  Unless 
you really want to manipulate the process, there's no reason to use the 6 
step process and I have standardized on Tetnal's 3-bath.  I use their 5L kit 
and mix just what I need to process each batch.  I process 10 sheets in 
250ml of chemistry, or 40 sheets per liter; this is 8 sheets shy of Tetnals 
stated maximum quantity of film/liter and quite ecenomical.  Kodak's kit is 
a pain to mix in small quantities and I have found it took almost as long to 
measure/mix the needed quantities as it did to process the film.

A different issue regarding chemistry...  Kodak stopped using a formaldehyde 
(sp?) based stabilizing bath, whereas Tetnal does.  Formaldehyde is a 
recognized carcinogen, but it is also recognized as the best chemical to use 
in this application.  With care, it can be used safely.  All stabilizing 
baths need to be used outside the drum.

It's getting late, so if I missed anything let me know.

Regards, Pete

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