[LargeFormat] Photoflo & Jobo 3000 Series Expert Drums

[Richard Knoppow]

----- Original Message -----
From: "Skip Roessel" <skiproessel@mindspring.com>
To: <largeformat@f32.net>
Sent: Thursday, December 12, 2002 9:07 AM
Subject: Re: [LargeFormat] Photoflo & Jobo 3000 Series
Expert Drums


> Clive,
>
> Perhaps you could make up your own Rollo Pyro, from the
published recipe
> (Darkroom Cookbook):
>
>     Part A
>
>         Distilled water                        750ml
>         Sodium Bisufite                        20 grams
>         Metol                                          20
grams
>         Pyrogallic acid                        150 grams
>         Ascorbic Acid
>             (Vitamin C crystals)                10 grams
>         Potassium bromide                     1.5 grams
>         EDTA tetrasodium                        2 -- 5
grams
>         Add distilled water to make      one liter
>
>     Part  B
>
>         Distilled water                            900 ml.
>         Sodium Metaborate                    300 grams
>         EDTA tetrasodium                        5 grams
>         Distilled water to make one liter
>
> Working solution for an expert drum with 4- 8x10 films:
> 10 ml part A, 20 ml part B into 500ml water, (530ml total
volume)
>         at 68F/20C in Jobo drum, continuous rotation 25
rpm:
>
>         FP4 at ISO 100            6.0 minutes
>         HP5+ @ ISO 400        6.5 mins.
>         BPF 200 @ 200           6.0 mins.
>         T-Max 100                    6.5 mins.
>
>
> The EDTA is a restrainer.  All these compounds are
available from Photochem in
> Quebec, Canada if not closer.  His website:
> http://www.colba.net/~fotochem/index.htm
>
> Although it's quite a project to secure a scale and mix
one's own chemistry,
> it pays off very quickly.  Especially if one starts doing
things like gold
> toner....
> Skip
> skiproessel@mindspring.com
>
>
  In the USA scales can often be found at police auctions
(taken from drug dealers). One does not need a particularly
fancy scale.
  EDTA tetrasodium salt is not a restrainer. Rather it is a
sequestering agent to bind soluble minerals in the water.
  It is a good idea to boil water to be used for
photographic solutions. It should be boiled from three to
fifteen minutes and allowed to cool while standing
undisturbed. The clear water is decanted or syphoned off.
Boiling serves three purposes: 1, it precipitates some of
the carbonates in the water by converting them to insoluble
form, 2, it drives off dissolved gasses including the oxygen
from the air and chlorine (but not the ammonium-chlorine now
used in several cities, that takes an activated charcoal
filter), 3, it coagulates and precipitates any organic
matter in the water.
  If the water is filtered through an activated charcoal
flter, boiled and filtered through filter paper (coffee
filters will do) there well be little left in it to upset
photographic solutions. The activated charcoal filter should
remove trace metals, which the EDTA may not and boiling will
not.
  Traces of copper will cause fogging, traces of iron may
affect developers containing ascorbic acid.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com