Was the difficulty of replicating reticulation a result of thinner emulsions
in modern films?
On Thursday, 9 September 2021, 10:32:25 am NZST, `Richard Knoppow
<dickburk@xxxxxxxxxxxxx> wrote:
Some thoughts: The problem with pinholes and reticulation
from differences in temperature of solutions is a fall back to
the 1920s and 1930's, problems which should be far in the past.
Sometime around the late 1930's the standard temperature for
processing was changed from 65F to 68F. This was due to the
improvement in emulsion hardening. Previous to this maintaining
the temperature of all solutions within a couple of degrees was
considered vital. After the overall temp was raised the match
between solutions became less critical. Eventually, films were
hardened to take very high processing temperatures, on the order
of perhaps 80F. This allowed high speed machine processing. I
think that even now most color films can withstand quite high
temperatures.
Not sure of paper but the recommended temp for paper
processing seems to have gone up at the same time film processing
temps were increased. The increased hardness of the emulsions
also made the use of special "tropical" solutions and more
powerful hardeners less necessary.
It is interesting to me that some of the problems of nearly
a century ago have evidently returned.
My own experience is that my attempts to reticulate film
deliberately were not successful. I think I must have done this
some twenty years ago but didn't keep notes. It took virtually
ice water and nearly boiling water to cause any disruption. This
was probably some standard Kodak film. I wanted to see if I could
duplicate some special effects I had seen illustrated. The
original work had been done in, probably, the 1920's, so its not
surprising that modern materials were quite different.
Maybe we need to go back to chrome-alum stop baths. Chrome
alum is a very powerful hardener. It is acid enough to work as a
stop bath but needs to be refreshed quite often. When the pH
begins to rise, as it does from carried over developer, it looses
its hardening property and, eventually, begins to leave a green
stain. Formulas for chrome alum stop bath may be found in books
as late as the 1950's if not even later.
OTOH, if you are getting pinholes with a non-carbonate
containing developer, like D-76 or DK-50 or many others,
something else is wrong.
Ordinary acetic acid stop bath will not effervesce with
metaborate or borax developers so, again, if you are getting
pinholes with one of these developers something else is wrong. As
mentioned before its easy enough to test for effervescence by
mixing a few drops of your developer with a few drops of the stop
bath. As the Alka-Seltzer ads used to say "Listen to it fizz".
Plain water is suitable as a stop bath but is not
instantaneous. Also, one needs a long enough rinse with
sufficient agitation to wash out a substantial quantity of the
developer. If not, the acid in the stop bath will also cause
effervescence although the hardener should prevent pinholes.
This, of course, assumes you are using acid, hardening, stop
bath. If not, you should be using a water rinse, really an
intermediate wash, anyway.
On 9/8/2021 1:54 PM, `Richard Knoppow wrote:
The original formula for Rodinal is still secret but several
versions have been published in the century or more that its
been on the market. The alkali seems to be potassium hydroxide.
AGFA used potassium salts because their chemical business
produced a great deal of it and it was cheap for them to use
it. I had to look up the reaction between potassium hydroxide
and acetic acid. The article I found says there is no visible
reaction, which I presume means there is no effervescence,
which is quite visible when it happens. One can test for this
by making up a small quantity of Rodinal developer and acetic
acid stop bath (a few drops are all that is required) and
seeing if it bubbles.
Dektol or D-72, or most other print developers use sodium
carbonate as the accelerator. They quite definitely do
effervesce when acetic acid is added. Developers containing
metaborate (Kodalk) or borax do not. I am not sure of modern
developers, like T-Max or Xtol but, again, they are easily tested.
Modern film emulsions generally are hardened to the degree
that they will not develop pin holes when effervescing
developers are used but I am not so sure all current films are
"modern" especially those made by small companies who may be
using very old fashioned formulae.
Companies like Ilford and Fuji are not what I mean.
Rodinal has the virtue of being highly concentrated which is
a convenience for some but there are better developers on the
market.
On 9/8/2021 1:24 PM, Brian Smith (smithcbrian2) wrote:
IIRC Rodinal (which I used for years) uses potassium
carbonate. Certainly it's used in Pyrocat HD. I know this
because I make it up myself. So now I'm wondering why I've
never had the problem, except when developing lith film in
Dektol?
Regards - Brian
On Wednesday, 8 September 2021, 03:01:36 am NZST, `Richard
Knoppow <dickburk@xxxxxxxxxxxxx> wrote:
This is a very well known problem. It does not happen when
some other alkali than carbonate is used in the developer. Kodak
made a big deal of this for its use of Kodalk, i.e. metaborate,
in developers. It also does not happen with D-76 or other
developers using Borax. I can't think of any commonly used film
developer that uses carbonate as the accelerator these days. The
problem is not important for prints because the pin holes are too
small to be visible there.
The question is whether the pin holes were cause by
effervescence in the stop bath or in the fixer or whether they
were in the emulsion due to a manufacturing defect. The only way
to tell is to fix out unexposed film and examine it. There have
been cases of pin holes in the emulsion from manufacturing. Most
modern film is has emulsions that have been substantially
hardened in manufacture and should not suffer disruptions from
this cause.
On 9/7/2021 1:17 AM, Brian Smith (smithcbrian2) wrote:
IIRC the cause of the pin holes is using a developer containinghttps://web.archive.org/web/20190330122042/http://deardorffcameras.0catch.com/
carbonate. The carbonate reacts with the acid in the stop bath
to form tiny bubbles of carbon dioxide (gas), which results in
pinholes. I've observed this when developing line film in print
developer. Try changing developers. - Brian Smith
On Tuesday, 7 September 2021, 06:12:55 pm NZST, Ken Hough
<k4sb@xxxxxxxxxxxx> wrote:
Arista and stop bath and me, did not get along. I just use
water. Then a double fix and Heico. No more pinholes
From:
Ken Hough Retired from
Ken Hough Photographic Repair
I Specialized in all Deardorff products
219-406-6849
On Sep 6, 2021, at 10:30 PM, Janet Gable Cull
<janetgcull@xxxxxxxxx> wrote:
The cost of film has gone up along with everything else. My
preference is TriX but I'm looking for something... cheaper.
Some years ago I tried Arista film but it had pinholes in it.
Was that a problem at one time that has been corrected? I see
some names of films I'm unfamiliar with that are less than HP5
and TriX.
Any recommendations? Thank you.
Janet Gable Cull
Sent from my iPhone
--
Richard Knoppow
dickburk@xxxxxxxxxxxxx
WB6KBL
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