Re: [Leica] AM 50 (again)

["Mike Durling" <durling@widomaker.com>]

Interesting, John.  There are two Pyrocatechol/hydroxide developers in the
"Darkroom Cookbook".  Both are listed as "extreme compensating" developers.
In oversimplified terms this means that they are soft working and the
highlights do not build up density with overexposure.  I don't know if that
matches the characteristics of AM50.

Mike D

- ----- Original Message -----
From: "John B" <e.brackenbury@chello.nl>
To: "LUG" <leica-users@mejac.palo-alto.ca.us>
Sent: Sunday, February 24, 2002 8:41 AM
Subject: [Leica] AM 50 (again)


For those who are interested the following is a not a very good translation
of the amaloco instructions supplied with this developer.  It may shed some
light on it's equivalent developer from another manufacturer.  My experience
with this developer is that when everything is perfect (exposure,
temperature, development time, position of stars and planets etc) then it
really is a remarkable developer.  Slight deviations from perfection and
this developer is just like any other.

AM50 Gammanool

General

AM50 is a 1 shot fine grain developer, that is specially made to develop
films that have been exposed at their rated speed.  AM 50 is a surface
developer based on pyrocatechol / sodium hydroxide. By the high pH value it
is however no genuine balance developer.??????

Films, which are to be developed in AM50 must be correctly exposed, under or
over exposed film results in quality losses. In the case of the correct
exposure, negatives of undreamt-of quality with very fine grain, high
outline sharpness and extremely fine detail result. This applies both to
films of low as well as with high sensitivity.  Basically all exposure
indices can be developed in AM50. (read all films)

Packing

AM50 is available in small refillable bottles with screw-type cap. The size
of the bottle enables a simple refill from the refilling packing.  By this
method one always has fresh developer to work with, which for constant high
quality, is a prerequisite.  Additionally it offers max. Security to you.
Small packing 3 x 20 ml, refilling 60ml.

Savings through the use of the 20 ml. bottles: If all contents of a bottle
are not used, then the remainder in the same bottle can be kept and be
filled up to the filling mark with water. The additional dilution should be
noted on the bottle.

Usage
Mix only briefly before use with simple tap water to dilute.  After good
agitating the solution is ready for use.

Dilution

Normal 1 + 29/1:30. Example: for a certain developing tank, 250 ml. liquid
is necessary.  Begin with 232 ml water and add 8 ml. AM50 Thoroughly agitate
briefly, and bring up to working temperature.  The developer is ready for
the immediate use.  Use only 1:30 as working solution.

Minimum concentrate of AM50 per 35 mm film is 8ml.  After use the solution
no longer operates reliably and must be discarded.

Working temperature

Optimum results are obtained with a  temperature of exactly 20°C. Deviations
of more than 0,5°C are to be avoided. We therefore expressly indicate only
development times for 20°C.

Agitation

For 35mm films agitate constantly for the first 30 seconds then at 30 second
intervals 2x inversion of the developing tank.

For roll films agitate constantly for the first 30 seconds then at 15 second
intervals 1x inversion of the developing tank.  This agitation insures even
development with no, so named, bromide effect.

Exposure

Expose the film as recommended by the manufacturer.  This does not apply
however to Ilford Delta 3200 and Kodak tmax 3200 film.  See table.

Development table

The development times are exclusive of filling/emptying times, are expressed
in minutes and based on a developer temperature of 20°C.  The exposure index
and development times are based upon an average negative contrast.  The
development times are for 35 mm and roll films and are based upon our recent
experience with the film emulsions.  If your method of working is to over
expose by 1 stop then we suggest you reduce the development times by 20-30%.
This does not apply to Ilford 3200 and Kodak tmax 3200 films.

Film type            ISO          Exposed at            Development time

Agfapan APX 25       25/15°          25/15°                     7'30"
Agfapan APX 100     100/21°         100/21°                    10'00"
Agfapan APX 400     400/27°         400/27°                     8'30"
Fuji Neopan 100     100/21°         125/22°                     7'30"
Fuji Neopan Prof    400/27°         400/27°                     8'30"
Ilford Pan F Plus    50/18°          50/18°                     3'45"
Ilford Delta 100 Pro100/21°         100/21°                     6'30"
Ilford FP 4 Plus    125/22°         125/22°                     5'00"
Ilford HP 5 Plus    400/27°         400/27°                     7'30"
Ilford Delta 400 Prof   400/27°     400/27°                    10'30"
Ilford Delta 3200   3200/36°       1600/33°                    10'00"
Kodak Plus X Pro     125/22°        125/22°                     4'30"
Kodak Td X           400/27°        400/27°                     8'30"
Kodak T-Max 100      100/21°        100/21°                     8'00"
Kodak T-Max 400      400/27°        400/27°                     9'00"
Kodak T-Max 3200     3200/36°       1600/33°                    10'0"
Kodak T-Max 3200     3200/36°       3200/36°                    15'00"
Tura P 150           100/21°         100/21°                    10'00"
Tura P 400           400/27°         400/27°                     8'30"



Hope this is of interest



John B








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