[LRflex] Re: Old film ? 20 years is too old !
- From: David Simms <simmszee@xxxxxxxx>
- To: leicareflex@xxxxxxxxxxxxx
- Date: Fri, 22 Jan 2010 08:11:11 -0800 (PST)
Thank you, Nevin.
This morning, I intend to retake much of what was on that film so I can avoid
those nasty chemicals. The Farmer's reducer sounds pretty ok and I have used
potassium ferricyanide in printing. Nevertheless, it's probably easier to visit
the subject again.
In this case, the subject is one of our wonderful waterfalls. The way the
waterfall ice and the bottom cones evolves through the winter, particularly a
winter with large temperature swings such as we've had, is quite amazing. These
waterfalls always keep me guessing. Yesterday, despite +4C temperatures, the
waterfall I visited was displaying melting and corrosion of the cone while
substantial icicles were forming, on the cliffs, due to evaporative cooling.
The visuals never disappoint and looking at the falls through the eyes of
physics always provides an explanation.
Dave, in BC's North Thompson Valley
________________________________
From: Nevin B. Greninger <greninnb@xxxxxxxxxxxxx>
To: leicareflex@xxxxxxxxxxxxx
Sent: Thu, January 21, 2010 10:58:36 PM
Subject: [LRflex] Re: Old film ? 20 years is too old !
Hi from Nevin. This is related to the reduction of fog. This contribution
is intended to generate a meaningful discussion with the hope of input from
others to zero in on practical measures for fog reduction.
I just turned to my laboratory manual for a chemistry course I took in
chemical photomicrography back in the late 1950's. It has in it an
experiment on intensification and reduction of images for B and W film. But
this experiment involved some very dangerous chemicals.
One ought to consult the old Kodak data books and other books on the
chemistry of photography regarding reduction and intesification of images
for a clearer presentation.
The following pertains to a general discussion of reduction and
intensification. It will get one oriented towards pursuing the matter of fog
reduction forv black and white film.
First off there is a discussion of health and safety matters associated with
certain photographic processes that should take place.
One must take precautions and study the chemistry of cyanides and of
hexavalent chromium before working with them.
Chromium six compounds if injected or ingested in the human body attack
almost every organ of the body, resulting in cancer and death within a short
period...
(See the "Erin Brockovitch" Film - <
http://en.wikipedia.org/wiki/Erin_Brockovich_(film) >. Hexavalent chromium
is bad news Chromium trioxide is on the CDC list of toxic/dangerous
chemicals and my recollection is that it ranks about 15th on the list of
most dangerous chemicals known. It is a Class I Solid Oxidizer and a Class
I Corrosive - after 30 minutes of contact with the "damp" skin it breaks it
down the tissue and enters the blood stream as a full-fledged human
carcinogen. Hexavalent chromium is used by industry to reduce corrosion in
compressors - they run hot and need to be cooled. The largest utility
company in the USA, Pacific Gas and Electric, knowingly dumped for two
decades hexavalent chromium into the drinking water for several California
communities causing a great number of cancer deaths among animals and
humans. This was addressed and discussed in the movie "Erin Brockovich,"
starring Julia Roberts.
Undergraduate chemistry labs minimize the use of dichromate but it remains
an important chemical. Organic chemistry labs use cyanides but if these are
acidified they produce hydrogen cyanide - death or execution gas. Hydrogen
cyanide is nevertheless an important industrial chemical and is used in
organic synthesis.
One can consult Linus Pauling's Dover book - "General Chemistry" for a
discussion of cyanides and chromates. Pauling is considered by some as
America's greatest chemist. He won the Nobel prize in Chemistry in 1954 for
the Theory of the Chemical Bond and almost beat Crick and Watson to the
punch in figuring out the double-helix structure for DNA. Pauling had
proposed a triple-helix structure that pushed Crick and Watson to rapidly
speed up their studies - they didn't want Pauling to win another Nobel
Prize. His book, General Chemistry, is one of the great pieces of
chemical literature. The first two hundred pages are devoted to a discussion
of the elements of modern physics something that is needed to understand
chemistry rather than solely rely on "brute force" memorization. He is one
of the few great writers that incorporated descriptive chemistry in his
textbooks, The book costs under $20 from Amazon Dot Com.
I cannot recall all the details on intensification and reduction of images
but these following bits of info may jog the memories of those of you who
know more than I do about intensification and reduction techniques.
However, one must use extreme caution when working with certain chemicals to
avoid quick death or cancer, etc. Even trained chemists have met death by
making mistakes or being fatigued when carrying out certain operations.
For Reduction we have as follows.
Two reducer solutions making up Farmer's Subtractive Reducer.
Stock Solution A (250 ml of distilled water and 20 grams of potassium
ferricyanide)
Stock Solution B (750 ml of distilled water and 225 grams of sodium
thiosulfate)
There is another solution, Formalin Hardener (one liter of distilled water,
10 ml of Formalin (37 %), and 5 grams of sodium carbonate (monohydrate)
For Intensification we have the following.
Intensifier Bleach: (90 grams of potassium dicromate, 64 ml of hydrochloric
acid CP , and water to make one liter)
Farmer's Subtractive Reducer requires hardening before its use. The
negative is placed in the hardener for about three minutes and then fixed
before further treatment. One part of Solution A Farmer's Reducer and three
parts of Solution B are mixed with 30 parts of water added. The negative is
put in this solution but the reduction must be watched closely so that it
may be taken out at the proper time. It is then washed with water.
Farmer's Proportional Reducer uses the same stock solution as Farmer's
Subtractive Reducer except in different proportions. The negative is
hardened and fixed as suggested previously. One part of Solution A is mixed
with 10 parts of water, and one (1) part of Solution B is mixed with 1 part
of water. The negative is allowed to stand in diluted A for about 2 minutes
and then put directly into diluted B for 5 minutes and washed thoroughly.
The Intensifier Bleach is diluted - 1 part bleach with 10 parts of water.
before bleaching, the negative is hardened with Formalin Hardener. The
negative is bleached 3-5 minutes and then washed thorougly with water. The
negative is then developed in Kodak D-72. Fixing after redevelopment is
unnecessary.
Hopefully, this input will stimulate meaningful discussion about reduction
of fog and the cautions one must take in the use of certain chemicals.
Enjoy the New Year but use caution when working with chemicals. Consider the
risks and benefits in doing certain things.
Contributed by 73-year old Nevin a retired chemical engineer who enjoyed his
graduate studies at Penn State in mathematics and Cornell in science and
enjoyed the teaching of calculus and differential equations for about six
years. He also studied solid oxidzers in great detail while working in
research, preparing a lengthy report on them for DOT. He plays mainly with
his toy - a Nikon F100.
----- Original Message -----
From: "David Simms" <simmszee@xxxxxxxx>
To: <leicareflex@xxxxxxxxxxxxx>
Sent: Thursday, January 21, 2010 11:01 PM
Subject: [LRflex] Old film ? 20 years is too old !
> After successfully exposing and developing a 10 year old roll of Agfa
> APX25, I decided to push my luck with a roll of Efke (Adox) KB17 which had
> an expiry date of 1989 on it.
> After researching development times (I settled on 8;15 in D76 1:1) i gave
> it a try. The result...a film that shows generalized fogging, perhaps a
> zone 3.5 when transferred to the print.
> Oh, i had also done a pre-wet of 5 minutes as I usually do.
> Conclusion: If you have some old films around, 10 years or younger, shoot
> them but don't use the stuff for that irreplaceable moment when you've
> stepped onto the peak of Everest or K2.
>
> Just maybe...could I pull the film through some bleach to get rid of that
> fogging ? any ideas out there ?
>
> Dave
>
>
>
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