Some Informationabout B&W Darkroom
Work
Go to other
interesting Link Collections Digital Truth
PhotoSource (
Brilliant collection of themes and links)
Some results about
research on the
Ilford film washing
procedure |
The method works,
however
I recommend to use
more water if there are 2 films in a
tank. |
Download an article with
a detailed report about measurements of film washing kinetics for
several film types here and modify your procedure:
The article as .pdf file for downloading
There is an interesting and
supporting comment af Marc Torzynski about this paper at another
place
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Washing prints:
(Same text is now included in pdf-file above about film
washing)
II've been asked frequently what are my recommendations for washing
prints?
Here they are:
Fibre paper:
I follow the recommendation of AGFA: a bath of 2% Potassiumcarbonat
is used to open the fibres of the paper. Then my prints are washed
in a Kaiser tray where the incoming water is guided in a way that
the water together with the prints is continuously moved. After
some time (10 - 15 min) I catch a print (18x24cm), hold it on one
corner, wait until the continuous water stream at the opposite edge
turn to droplets, and catch now the water for a potassium
permanganate test as depicted in above. In case no colour change is
observed a give additional 10 minutes, if colour is changing, I
repeat the test every 5 minutes until colour change does not occur.
Since I follow this procedure I haven't found any problems with my
prints even when they are exposed to daylight for years.
RC-paper:
RC-Paper is too stiff to be washed together with fibre based paper.
A few sheets RC paper obstruct the movement in the tray
completely.
So I acquired a special RC paper washer: A usual 30 x 40 cm
tray, with a tube at the one end, where several small holes
distribute water into the tray, and a row of holes in the tray at
the other end as water outlet. After a while I found that the
amount a water spilled was large, compared with the amount of water
used per surface area of a film. And this amount of water should be
even less. because the thickness of a RC paper emulsion is much
less than of a film emulsion.
To check for small water supply (2 l/min) the movement and the
distribution of the water in the tray I throwed some
Potassium permanganate crystals into the water. I saw that at these
low speed the flow was just at the surface of the water in the
tray, but at the bottom, where usually the print are located when
washed, practically no water movement occurs. So this tray used as
a print washer is badly designed and useless, because it fails
completely its task: To provide as much fresh water to the print as
possible.
Today, as a conlusion, I wash my RC prints completely separate from
the fibre prints. When I start to wash them, each print is
individually flushed under running fresh water, which is running
quite slow (app. 0.2 - 0.3 l/min) just to remove the water loaded
with hypo. Then the prints are collected in a tray with fresh water
and stacked one above the other. For this I use a 18 x 24 cm tray
with app. 1 l water in. After a while (app 30s) I start the
same procedure, i.e. each sheet is hold individually under slow
running fresh water and put into another tray with fresh water. The
main principle is to follow what I have found for film washing:
reduce the amount of take over as much as possible .
Before I transfer the last sheet into the next tray I examine it
with the Potassium permanganate test as depicted above. As long as
I can observe a colour change I proceed. When the colour change is
no longer visible, I give two additional wash batches. It is
astonishing how small the number of batches is: for 20 18x24cm
prints usually 4-5 batches are sufficient.
After all, my recommendation is to check the efficiency of washing
and control it as described. All other rules (apply exact
times and temperatures, specific agitation, and what ever...)
do not work reliable.
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Do you measure
temperatures and believe you measure correctly? Then read the
article about temperature measurement:
Bauanleitung für
Präzisionswaage
für Entwickleransatz für € 5.-
(Sorry, currently only
in German, an instruction how to build a precision scale for
weighing chemicals for photograhic purposes (Investment: €
5.- ):
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