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Different methods of film
processing
by Martin W. Baumgarten
The basic different manual film processing methods employed by amateurs and professionals are:
Rack and tray method: This uses a stationary rack upon which the film is wound upon and then
immersed into a tray or deep tank. The rack also acts as the film drying
rack and usually had a special stand to hold it for loading and later
film drying.
Rewind Tank method: This has been around for well over 50 years and the G-3 Rewind Processor
is still being made and sold by Arkay-Doran (via Regal Photo Products)
in Wisconsin. Film is attached to a reel and fully would onto it
emulsion outward, then end is attached to the other reel in the tank.
Water and chemistry is added via a top flanged port and drained via
bottom drain with a rubber stopper. Film is wound continuously from one
reel to the other, at a rate of one full transfer of film to the other
side per minute...stopping only for chemical changes, water washes etc. Separator Strip method: This method
employed an acetate length of filmbase that was dimpled by a dimpling
machine. Film was wound with this strip around a clear take up reel and
was then processed by immersing it into a print tray or via deep tanks.
The dimples kept the film's emulsion from touching anything (dimples
were along the very edges of the film), and allowing the chemicals to
work on the film.
Reel & Trough: This method used a large reel, about 18 inches or so in diameter upon
which the film was wound emulsion outward. The reel fit into a trough
holding about a gallon of chemistry and generally having a drain for
ease of changing chemicals. The reel had to be continously rotated to
allow for even processing.
Motorized Rewind Processor: This was a
fully automatic motorized rewind processor which allowed one to process
up to 200ft of movie film from 16mm to 70mm in width. The top motor unit
also held the reels and was then fitted atop a special developing
tank...once fitted the unit combo was light tight and room lights could
be turned on until the next chemical change step. Also extra tanks came
with this...so you just had to lift the motor unit and then fit in atop
the next chemical tank.
Spiral Reel Processing Tank: This method
uses a spiral reel(s) upon which the movie film is loaded and then
immersed in chemistry for processing via trays, a special tank made for
that given reel, or deep tanks. This is perhaps the method ensuring the
most professional results.
Tube or Hose Processing: Back some years....when many folks wanted to process their own personal home
movies for various personal reasons.....this method came into being. A
25ft length of vinyl or rubber hose was used that was just slightly
larger in diameter than the gauge of the film. A stopper was used on
either end, and these were referred to as 'snakes' by the 'beat'
generation of the 50's. The hose was coiled in a large pan to control
it...chemistry was removed by pulling off the stoppers and letting it
drain, and then adding the next chemical or wash water to the hose and
stoppering it up again. A bit clumsy to work with but can be quite
effective.
Bucket and Tank Type Methods: Film is sort
of carefully scrunched up into a bucket or still film processing
tank...which already has a pre-wash with a wetting agent in it...so that
as the film is immersed it is all evenly made wet, which will allow for
more even processing. Drawbacks are insufficient processing agitation,
scratch and damage marks etc. The bucket method works best...but requires more chemistry.
Roller-transport Film Processor: Machines such as the MicroFilm Processors for 16mm (and other gauges), Kodak
Versamat 5AN and others that employed hard machine rollers in which the
film was initially pulled thru by a 'bullet', and then taken up gently
by a take up reel on a slip-clutch driven unit. Various versions of these were made.
Standard Motion Picture Film Processors:
Small versions of professional type motion picture processors were
avaiable, made by Kodak (SMA 7244 Supermatic 8 film processor for table
top use), Cramer Company of Sarasota, FL, and Jamieson Film Company of
Dallas, TX, and others. These required processing machine leader like
their full size industrial counterparts...but these machines are
tabletop sized, or floor models that are only about 4ft long and 2ft
wide. By far one of the best film processing methods....although due to
their smaller size...only small quantities of film could be processed
within an 8 hour day...especially color reversal films which required
agonizingly slow running speeds. Average daily film output was about 6 -
10 rolls of color reversal, and about 10 to 20 rolls of color (based on
Super 8's cartridge length of 50ft per cartridge).
I hope this helps you out some. Let me know if you require any technical details should you want
to process any film.
Martin W. Baumgarten © 2000
Plattsburgh Photographic Services
http://lavender.fortunecity.com/lavender/569/index.htm#Processing
Advantages & Disadvantages of Various Processing Methods (only the most
obvious are listed)
by Martin W. Baumgarten
SPIRAL REEL PROCESSING:
Advantages:
(1). Film is processed uniformaly, all at once.
(2). Processing times are fairly short compared to most other methods.
(3). Reversal exposure, if used, is easy to accomodate.
(4). Without any movement of the film, there are few possibilities for
processing marks.
Disadvantages:
(1). Usually requires more chemistry that some other processes, except for the
Superior Bulk Film equipment which required only 16oz per Super 8mm film.
(2). Can be hard to load and unload at times, adding time spent in total
darkness.
(3). Can be difficult to maintain higher temperatures due to the open surface
design.
(4). Existing equipment can be hard to locate and new items are expensive.
REWIND PROCESSING:
Advantages:
(1). Uses little chemistry, only 1 liter per 2 - 50ft Super 8mm films or 100ft
of Regular 8mm or 16mm film
(2). Requires little space.
(3). Easy to load and unload.
(4). Easy to maintain temperature as processor will sit easily in a large tray
or pan of water to maintain temperature.
(5). Low cost of equipment, only $79.95 to $99.95 for a processor new.
(6). Due to the method used....is very forgiving of processing time/temperature
errors.
Disadvantages:
(1). Chemistry oxidises quickly if not reused soon.
(2). Extremely long processing times....1&1/2 hours for 1-50ft film, and about
2&1/2 hours for 2-50ft films or 100ft 16mm or 100ft Regular 8mm
(3). New units don't have the reversal exposure window....so removing the cover
and winding the reels manually while exposing to light is a pain at times.
(4). The constant winding back and forth, one full wind per minute, thus about
two turns of the handle per second, can easily tire many people out by the time
they are finished.
HOSE PROCESSING:
Advantages:
(1). Low cost materials involved.
(2). Uses little chemistry
(3). Can be rolled up to operate in a small space (but rewind processing beats
them all)
Disadvantages:
(1). Hassles of loading film and unloading from the vinyl hose.
(2). Hassles of chemistry pouring in and out....but not too bad.
(3). Problems of reversal exposure unless you use a clear hose...which means you
have to remain dark until the light steps.
(4). Potential for disaster if you aren't careful.
(5). Best used to lengths not longer than 25ft.
RACK & TANK(or TRAY) METHOD:
Advantages:
(1). Cheap, you can make your rack yourself
(2). The rack is also your drying rack...no need to remove film until dry.
(3). Easy to move film from tray to tray or tank to tank...or just drain out
tray, and refill with next step.
Disadvantages:
(1). Lots of aerial oxidation due to the open trays.
(2). Requires quite a bit of chemistry, up to half gallon or gallon depending on
your design.
(3). Accidents with physical damage to film if you aren't careful handling it...but
this is true with every method.
(4). Added cost since you have to use more chemistry, and thus mix up more.
Martin W. Baumgarten © 2000
Plattsburgh Photographic Services
http://lavender.fortunecity.com/lavender/569/negtoposdeveloper.htm
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