From: Ed Inman (email suppressed)
Date: Sat Mar 25 2006 - 12:36:44 PST
>----- Original Message -----
>From: Steven Budden
>I'm just switching to an Arkay G3 rewind processing tank which holds 32 ounces.
>Anyone have any advice about how many times I can use the dichromate bleach to process 16mm 100' rolls in this tank?
>Also, have a similar question about D-19 developer... how many times I can use it as first and second developer (with decent results) for Fomapan vs Tri and Plus x reversal?
Hi Stephen,
First, let me say I'm not a fan of the G-3 rewind tank--it is tedious as heck to use and results tend to be very unpredictable. I would personally just as soon wad the film up and swish it around in a bucket as use a G-3. However, if you really want to use this tank I suggest using fresh chemistry for every batch, or at least every few films. I have also heard that it helps to mix your dichromate bleach at double strength. Do not use permanganate based bleach in this tank at all--it will not work.
Below is a processing paper I wrote a while back which includes a special section with instructions if using a rewind tank. Please note that I am just an amateur and offer no guarantees regarding any of these processes whatsoever, but I hope it can be of some help:
This document is divided into the following sections:
1. SUGGESTED SOLUTION FORMULAS.
2. SUGGESTED PROCESS FOR CONTINUOUS IMMERSION TANKS.
3. ALTERNATIVE BLEACH AND CLEARING BATH FORMULAS WITH ALTERNATE
SUGGESTED
PROCESS FOR CONTINUOUS IMMERSION TANKS.
4. SPECIAL PROCESSING INSTRUCTIONS FOR USING G-3 STYLE REWIND TANKS.
5. BLEACH WARNING.
6. GENERAL TIPS AND TROUBLESHOOTING GUIDE.
------------------------------------------------------------------
SECTION ONE:
SUGGESTED SOLUTION FORMULAS
Note: to convert these liter measurements to a one gallon kit, simply
multiply these amounts by 4 (or 3.785 if you want to be precise about
it).
FIRST DEVELOPER: Add 9.5 grams of sodium thiosulfate to 1 liter of Kodak
D-19 developer regular strength.
R-9 BLEACH: To one liter of water add 9.5 grams of Potassium Dichromate
and
12 ml of concentrated Sulfuric Acid.
CB-1 CLEARING BATH: To one liter of water add 90 grams of Sodium
Sulfite.
SECOND DEVELOPER: Use standard D-19 or paper developer like Dektol or
Polymax T regular strength.
FIXER (Optional): Use Kodak Rapid Fixer or similar.
HYPO CLEARING AGENT: Use Kodak Hypo Clearing Agent, or similar.
PHOTO-FLO: Use Kodak Photo-Flo or similar.
------------------------------------------------------------------
SECTION TWO:
SUGGESTED PROCESS FOR CONTINUOUS IMMERSION TANKS
The recommended starting point times for a standard (non-rewind) tank at
20C (68F) is:
FIRST DEVELOPER: 7 min.
RINSE: 3-5 min. (change water frequently)
BLEACH: 1-2 min.
CLEARING BATH: 2 min.
RINSE/RE-EXPOSE with bright white light. (You can't overexpose at this
point)
SECOND DEVELOPER: 5 min.
Film may now be washed and treated to photo-flo (to minimize drying
marks).
To harden emulsion (optional) the film may additionally be treated to
hardening fixer at this point then washed and dried normally.
To dry, string a line across the room and loop the film (emulsion side
up)
over and over the line. Dry for approx. 45 minutes, then spool the film
emulsion side out on your projector reel for exhibition.
------------------------------------------------------------------
SECTION 3:
ALTERNATIVE BLEACH AND CLEARING BATH FORMULAS WITH ALTERNATE SUGGESTED
PROCESS FOR CONTINUOUS IMMERSION TANKS.
ALTERNATIVE BLEACHING SOLUTION:
Many people prefer this alternative bleach formula to the traditional
dichromate based bleach:
Solution A:
Potassium permanganate 2g
Water to make 500ml
Solution B:
Water to make 500ml
Sulphuric acid, conc. 10ml (add acid TO water!)
For use, mix parts A & B in equal parts (1:1) just before use. Use once
and
discard.
CLEARING SOLUTION FOR USE WITH PERMANGANATE BASED BLEACH:
Sodium metabisulphite below may be replaced with potassium
metabisulphite.
Sodium metabisulphite 25g
Water to make 1 liter
REVISED PROCESS FOR USE WITH ALTERNATIVE BLEACH/CLEARING BATH:
Bleach film for five minutes with constant, vigorous agitation. Wash for
two minutes then treat to clearing bath for two minutes. All other
process
times and procedures explained in Section Two remain the same.
------------------------------------------------------------------
SECTION 4:
SPECIAL PROCESSING INSTRUCTIONS FOR USING G-3 STYLE REWIND TANKS.
Note: Double strength R-9 style dichromate based bleach should be used for reverse
processing
in the G-3 Rewind Tank. Sufficient agitation is not possible with this
tank to use permanganate type bleach.
Only one liter or quart of solution is required in this tank for
processing
up to 100 ft. of Super 8 or 16mm film.
Since it is a "rewind" tank, the operator must continuously wind the
film
back and forth from one reel to another. At recommended winding speed of
2
turns per second, a complete wind of one 50-ft. Super 8 film would be
about
40 seconds from one end to another. For 100-ft spool of 16mm (or two
Super
8 films stapled together) the time would be one minute.
IMPORTANT:
1. Emulsion should be face out.
2. Unless Prebath PB-3 is used when film is first submerged, tilt the
tank
and pour in enough water so that the reel with no film is wet and reel
with
film is dry. Then wind dry film onto wet reel so that emulsion is
uniformly
made wet.
G-3 PROCESSING STEPS:
SOLUTION and suggested NUMBER OF WINDS AT 68F (20C):
FIRST DEVELOPER: 12 (Or 8 at 80F)
RINSE: 4 (change water each time)
BLEACH: 10 (8 at 80F)
CLEARING BATH: 8 (6 at 80F)
Now remove cover of tank, add water, and re-expose film under a bright
200
to 500 watt light or in sunlight for two to three complete winds.
Cover tank and continue:
SECOND DEVELOPER: 8 (6 at 80F)
You may now rinse film (5 winds running water) and dry, OR if you want
to
harden emulsion add the following steps:
RAPID FIXER: 3
RINSE: 2
HYPO CLEARING AGENT: 2
RINSE: 5 (running water)
PHOTO-FLO: 2
------------------------------------------------------------------
SECTION FIVE:
BLEACH WARNING
Potassium Dichromate and Sulfuric Acid are hazardous chemicals which
should
be treated with extreme care and handled as hazardous waste. Potassium
Permanganate is considered less hazardous than is Potassium Dichromate,
however both solutions employ the use of sulfuric acid which can blind
or
kill individuals if not properly handled. Always add acid to
water--never
water to acid. If in question, the bleach formula should be made and
handled only by a qualified chemist.
------------------------------------------------------------------
SECTION SIX:
GENERAL TIPS AND TROUBLESHOOTING GUIDE
As a general rule, remember:
If too dark, increase exposure or time or temp. of first developer.
If too light, decrease exposure or time or temp. of first developer.
One source to order hard-to-find photo chemicals is Photographer's
Formulary (Phone 1-800-922-5255). Note: They only sell sulfuric acid in
a
48 percent solution so you will need to use 25ml for a liter of bleach
instead of the 12ml you would use of concentrated solution.)
ADDITIONAL TIPS:
1. By adding an optional rinse between the bleach and the clearing bath,
you can probably extend the useful life of the clearing bath. For most
consistent results always use fresh chemistry.
2. If highlights appear to be not fully reversed (I.E. gray image where
there should be white) the bleach is exhausted or you need to increase
bleach time.
3. If yellow or brown stain appears anywhere in film, clearing bath is
exhausted or you need to extend clearing bath time.
4. If fixer erases part of the final image, you did not fully re-expose
or
redevelop the film or your second developer is exhausted.
5. For making titles or other high contrast applications, you may
substitute Kodalith developer in the first and second development
stages,
or use as a negative developer.
6. The same formulas and processes as described in sections one through
three are also suitable for processing 35mm black and white slides from
most B&W films. Slower emulsions such as T-Max 100 or Ilford FP4 are
generally recomended and should be exposed at approximately one-half
their
normal rated speed for best results.
---- The procedures and formulas presented here are based only on practical observation and experimentation rather than formal training. These recomendations carry no guarantee whatsoever and I am always open to suggestions as to how these recommendatioins can be fine tuned for more consistent results. __________________________________________________________________ For info on FrameWorks, contact Pip Chodorov at <email suppressed>.