Foma Reversal film in 120?

"____" wrote in message
...
Back when I was doing a bit of film testing and article
writing for View
Camera Magazine the folks at Foma sent me test rolls of
the Fomapan R
film for review.

For reasons I can't go back to for loss of the info I
found that
processing the film myself was not an option. Something
about the
process did not appeal to me or was rather nasty.

I looked at two labs, one was DK-17? in California that
wanted a vast
sum per roll. The other was Duggal in NYC. Duggal
processed the film and
it was beautiful. Not sure if they still offer the service
or are in
business.

Unfortunately Steve Simmons and his Buddy Tim lost my film
in their
haste to split View camera and Camera Arts Magazines.

My article was never published related to the Fomapan
Films.

I do however have a scan or two from the Fomapan and one
roll of the
reversal film.


Snipping here...
I wonder what the problem was with the reversal
process? Were you using a chemical reversal that used
something nasty? Typical color reversal processes use
borains and other chemical reversal agents.
Simple B&W reversal is not too difficult to do but
requires some experimentation. The first developer is rather
high contrast compared to the ususal negative developer.
That is because most reversal is done to obtain
transparencies for direct viewing or projection and the
contrast of the final reversed image is controlled by the
first developer. Because of the high contrast there is very
little room for error in exposure or development. The first
development is the only one that is critical, the remaining
steps are all done to completion.
As you probably know the emulsion of film contains
silver halide particles having a wide range of sensitivity
to light. If all the particles had the same sensitivity the
film would be unable to record continuous tone subjects. In
fact, the distribution of sensitivity is what differentiates
low and high contrast media. In pictorial film there are
some halide particals that have such low sensitity that no
practical amount of exposure to light will make them
developable. These will remain in the film after development
and cause veiling when the film is reversed. Early attemps
at reversal required very high exposure levels, that is a
serious reduction of film speed, in order to obtain anything
like a good revesed image. It was discovered that these very
fine grain particles could be eliminated by the use of a
mild halide solvent in the first developer. If the amount of
solvent is chosen correctly the film speed for reversal is
not much different than its speed as a negative and the
reversed images will have clear highlights. A number of
solvents have been used. The most common ones are
thiosulfate (hypo) and in more advanced formulas
thiocyanate, which is a more powerful solvent with less
effects on fogging. The amount of solvent is dependant on
the nature of the emulsion so no single formula will be
optimum for all films.
The first developer is a highly active, medium high
contrast formula. Typical reversal formulas resemble
developers like Kodak D-19 with the addition of the solvent.
Some are even higher contrast and may contain some hydroxide
to accelerate development. Actually a good print developer
like Dektol will work. The next step is bleaching. The usual
bleach uses either dichomate or permanganate as the bleach.
These remove the metallic silver from the first development
but leave the remaining halide. Dichromate bleach is the
better of the two but permanganate is often used because its
somewhat safer. Both require the use of sulfuric acid.
After bleaching the film is usually treated in a clearing
solution to remove stains left by the bleach. This is
usually just a sulfite or bisulfite bath. The next step is
to make the remaining halide developable. If a silver
generating developer is used a the halide must be made
developable by either re-exposing it to strong light or
treating it in a chemical fogging agent. If a sulfide
redeveloper is used the flashing or fogging step is not
required.
Redvelopment or second development is done in a high
activity developer like Dektol or in a sulfiding solution.
When sulfide is used the result is a sepia image and only
washing is needed to complete the process, and, as mentioned
above, the fogging step is not required. When a silver
generating developer is used a final fixing step is
necessary because some very insensitive halide particals
will have survived both the solvent in the first developer
and the re-exposure and must be removed. After the fixing
step the film is washed and the process is complete.
That's it. I suspect the use of the dichromate or
permanganate bleach may have been the problem mentioned by
the original poster. Dichromate bleach used to be available
off the shelf as tray cleaner and is used in a number of
alternative printing processes. It must be handled with care
both because of the strong acid in the bleach and because
dichromate is a suspected carcinogen. This makes both hard
to obtain these days.
Typical formua for reversal first developers contain
anywhere from about 5 grams per liter to 15 grams per liter
of thiocyanate but some contain as little as 2 grams per
liter. The only way to determine the optimum amount is to
experiment.


--
---
Richard Knoppow
Los Angeles, CA, USA

Richard Knoppow wrote:

Typical formua for reversal first developers contain
anywhere from about 5 grams per liter to 15 grams per liter
of thiocyanate but some contain as little as 2 grams per
liter. The only way to determine the optimum amount is to
experiment.
_____
Richard,

I have several reversal formulas in my files. They look very similar in
terms of overall procedure. If you like, i can dig them out and put
them on this forum.

Many years ago i prepared an article on the subject of making 35 mm B&W
slides for Peterson Photographic magazine. I never got around to sending
them the sample slide and text. The test slides are still in my
archives. I used Kodak's Panatomic-X which, as we all know, is no longer
available. The results were very good if i recall. I have never tried
to make 120 format slides. In my case they would be 6x7 cm format from
my Pentax 6x7.

/ John

--
Regards / JCH

"jch" wrote in message
news:BFKpk.190218$gc5.62112@pd7urf2no...
Richard Knoppow wrote:

Typical formua for reversal first developers contain
anywhere from about 5 grams per liter to 15 grams per
liter of thiocyanate but some contain as little as 2
grams per liter. The only way to determine the optimum
amount is to experiment.
_____
Richard,

I have several reversal formulas in my files. They look
very similar in terms of overall procedure. If you like,
i can dig them out and put them on this forum.

Many years ago i prepared an article on the subject of
making 35 mm B&W
slides for Peterson Photographic magazine. I never got
around to sending them the sample slide and text. The test
slides are still in my archives. I used Kodak's
Panatomic-X which, as we all know, is no longer available.
The results were very good if i recall. I have never
tried to make 120 format slides. In my case they would be
6x7 cm format from my Pentax 6x7.

/ John

--
Regards / JCH
I wouldn't mind having them although I suspect I may
already have some. Kodak has some current formulas for
reversing its motion picture film. I think I have those on
this computer somewhere.
Reversal of B&W was very common before video tape drove
film off the market for home movies and some industrials.
Processing was no mystery. I have never found definite
information about the differences between ordinary negative
emulsions and those intended especially for reversal but
think it may have been partially the distribution of halide
particle sizes to insure enough fine grain particals to
insure sufficient density in the shadows of the reversed
image and likely also some extra hardening to withstand the
more than usually high pH developers and highly acid bleach.

Color reversal is not quite the same because the silver
image from the first development does not have to be
bleached out until a final bleaching step at the end which
removes all the metallic silver leaving only the dye image
behind.


--
---
Richard Knoppow
Los Angeles, CA, USA

Richard Knoppow wrote:

I wouldn't mind having them although I suspect I may
already have some.
_____
R,

Will dig through my notes and such in the next few days, and post what i
find.

Have done both B&W and colour reversal films (Agfa, Ektachrome, GAF)
years ago. Pretty simple really. The colour films need constant temps,
but that is easy to achieve.

/ John

--
Regards / JCH

In article ,
"Richard Knoppow" wrote:

I wonder what the problem was with the reversal
process?

I want o say it required Formulin, and I did not have it. Coupled with
producing results for a job I intended to be paid for and a limited
amount of practice material swayed me towards having someone else to
blame

Never the less I see Duggal is still in business, where the Dr15? lab is
nowhere to be found.

--
Reality is a picture perfected and never looking back.

"____" wrote in message
...
In article
,
"Richard Knoppow" wrote:

I wonder what the problem was with the reversal
process?

I want o say it required Formulin, and I did not have it.
Coupled with
producing results for a job I intended to be paid for and
a limited
amount of practice material swayed me towards having
someone else to
blame

Never the less I see Duggal is still in business, where
the Dr15? lab is
nowhere to be found.

Formalin or formaldehyde was used as a pre-hardener. It
maintains its hardening in alkaline solutions like
developer. Because the first developer in reversal
processing is often strongly alkaline it may soften the
emulsion too much. This was much more likely with film of
the past than modern film, which has much harder emulsions.
Formaldehyde was also commonly used in color processing as a
final rinse both as a hardener and as a stabilizer for the
dye. Indeed it is nasty stuff.


--
---
Richard Knoppow
Los Angeles, CA, USA

"Richard Knoppow" wrote

Formalin or formaldehyde was used as a pre-hardener. It maintains its
hardening in alkaline solutions like [strongly alkaline] developer

Is that the sole reason for the inclusion of paraformaldehyde
in lith film developers? Can it be safely excluded if one
is willing to handle the film gently.

--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation: F-Stop Timers, Enlarging Meters
http://www.darkroomautomation.com/da-main.htm
n o lindan at ix dot netcom dot com

Nicholas O. Lindan wrote:
"Richard Knoppow" wrote

Formalin or formaldehyde was used as a pre-hardener. It maintains its
hardening in alkaline solutions like [strongly alkaline] developer

Is that the sole reason for the inclusion of paraformaldehyde
in lith film developers?

No. The paraformaldehyde is there to buffer the sulfite so the solution has
a very low effective concentration, but reserve capacity to manage
oxidation. Lith developers work by infectious development, and the higher
the sulfite concentration, the worse they work.

Can it be safely excluded if one
is willing to handle the film gently.

As long as you are not relying on infectious development. If you are serious
about line work, or half-tone work, I recommend developers with
paraformaldehyde, acetone, or some such, in their formulae.

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 05:50:01 up 12 days, 11:56, 4 users, load average: 4.67, 4.79, 4.33

Hello,

I would certainly be interested in developing Efke 25 4x5 as a positive.
Then I could print to get the effect that I would normally get only on
a 4x5 neg. It would save me a lot of time because I wouldn't have to
make a film copy of the neg and then printing the resultant positive to
get back the image that I have on the negative. Save me a step and a
lot of work.

Cheers,
Bogdan

jch wrote:
Richard Knoppow wrote:

I wouldn't mind having them although I suspect I may already have
some.

_____
R,

Will dig through my notes and such in the next few days, and post what i
find.

Have done both B&W and colour reversal films (Agfa, Ektachrome, GAF)
years ago. Pretty simple really. The colour films need constant temps,
but that is easy to achieve.

/ John


--
__________________________________________________ ______________
Bogdan Karasek
Montréal, Québec bogdan(at)bogdanphoto.com
Canada www.bogdanphoto.com

"I bear witness"
__________________________________________________ ______________