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Photo Engineer
04-29-2007, 11:35 AM
This is a Lith emulsion published by Grant Haist that he has taken from the work of Steigman. It is an SR (single run) emulsion that gives high contrast results, and very high contrast results in a Lith developer.

I have not tried this emulsion. I take it verbatim from Haist and urge you to buy the book from Grant. I also urge you to caution. See the notes below.

Solution I

Water 425 ml
Conc HCl (hydrochloric acid) 2 ml
Cadmium Chloride, CdCl2.2H2O 0.4g
Gelatin 20 g
Egg Albument 10% 2 - 3 ml

Solution II

Water 100 ml
Silver Nitrate 20 g

Solution III

Water 40 ml
Cadmium Chloride, CdCl2.2H2O 0.3 g
Sodium Chloride 7 g
Potassium Bromide 1.5 g
Na2RhCl6.18H2O (1 gram in 10,000 ml) 4 ml < Rhodium Chloride solution

Bring all to 55 C.

Add II to I rapidly with stirring. Follow at once with III. Add 12 ml of Potassium Iodide solution(1g in 500 ml). Heat to 60 dec C and hold for 1 hour. Add 12 ml of Magnesium Oxide solution (no concentration given) and then 3 g of Silver Nitrate in 30 ml of water. Add 12 ml of Rr340 solution ( 1 gram in 4000ml). ISO wash with Sodium Sulfate and then dilute to 250 ml total. Add 5 g gelatin and then heat to 60 C again for about 45 mins.

Note that no concentration for the Magnesium Oxide is given, nor is the identity of the Rr340 solution given. This is typical of all published formulas including the work of Haist and others. It also includes the Agfa reports from after WWII in which similar emulsions are described. It may also assume use of an active gelatin rather than a modern oxidized deionized gelatin. One does not know a priori which is meant.

So, the point being that replicating this work is difficult, but does show that a high contrast emulsion can be made by a single run procedure with no control. It has been done for years this way. And, it shows how difficult it is to reproduced an emulsion from a published or patented formula.

The patent might say "Add a Magnesium Oxide solution as is known in the art". Well, actually Magensium Oxide is not really soluable in water as it forms Magnesium Hydroxide (milk of magnesia) and so this may be a misprint meaning grams of solid, or it could mean that you use milk of magnesia. The formula is so old, I use it too to illustrate that the art and science of emulsion making can be just about completely lost over time.

You see, one just cannot say for sure unless several sources can be compared and without extensive research work.

PE

dwross
04-29-2007, 12:01 PM
You see, one just cannot say for sure unless several sources can be compared and without extensive research work.

PE

Ron:

Once again, you dangle tantalizing puzzles and inspiration to work/play/learn in the darkroom. You're a treasure.

xo, d

rmazzullo
04-29-2007, 12:57 PM
PE,

Thanks for posting this. It provides some very interesting possibilities. I am going to have more things to try out than I can shake a stick at.
(More material to print out....)

Thanks!

Bob M.

Photo Engineer
04-29-2007, 01:06 PM
Well, I decided to post a puzzle for you.

For the first one to decipher the 2 clues in the emulsion above that tells me whether it uses old or new type gelatins, I'll send the complete information. :D

The first posting of both in one post will bring the answer from me on-line here and a PM or e-mail to the person posting them with all of the information.

PE

dwross
04-29-2007, 01:13 PM
I'm game. I'll take a swing at embarrassing myself. Old, because of the addition of egg white for the sulfur??

Photo Engineer
04-29-2007, 01:27 PM
You have to get both. You didn't even get one. You were close, kinda.

PE

dwross
04-29-2007, 01:53 PM
Well, since their are only two sides to this coin...I'll go with new :). The new gelatins can be made inert (is that true for all of them. What's the formulation of the gelatin I buy from PF?) so sulfur in the albumen is necessary for the lith emulsion (??) The second clue is a puzzle. I'll guess the Rhodium chloride (that's another sensitizer, too, right?) Does it need to be in an acidic emulsion to work? Be kind if I'm hilariously off-base.

dwross
04-29-2007, 01:55 PM
grammar puzzle: can you spot the typo (or as a friend more honestly calls them: "thinkos" ?

rmazzullo
04-29-2007, 02:04 PM
OK, I am going to take a shot at it...

New type gelatins, and the Hydrochloric acid and potassium bromide remove whatever sulfur is left...?

Oh well....

Bob M.

rmazzullo
04-29-2007, 02:22 PM
Not even close, eh?

ben-s
04-30-2007, 08:32 AM
Probably way off, but I'll go with old, active gelatin, my reasons are as follows:
1: The silver nitrate solution is dumped into solution 1 rapidly (this seems consistent with old formulas?)
2: The ripening stage seems fairly short - 60deg C for 1 hour

Way off? :D
Go on, laugh at us

Photo Engineer
04-30-2007, 08:37 AM
Nah, I'm not laughing.

I'm so used to modern emulsions Ben that it took me a while to read these old ones myself so I got poor results, as you cannot always tell which type they are just by reading unless you catch the signals. The people publishing love to leave out lots.

So, it is like reading Italian for years and then trying to read Latin. There is a big difference and I had to learn that myself, as none of these old-timers are around now to tell us.

Grant didn't give us the clues either.

PE

rmazzullo
05-02-2007, 08:25 AM
One more attempt...

This is using old (active) gelatin because cadmium chloride and the gelatin itself were components of early emulsion attempts to move away from wet plates (collodion).

Can't lie about this; I had to dig in a few history books for this, and I could have misinterpreted the role of the cadmium. But it was worth a shot...

Thanks,

Bob

Photo Engineer
05-02-2007, 08:54 AM
Bob;

Cadmium was used up till 1970, and is not the answer.

Thanks anyhow....

PE

rmazzullo
05-02-2007, 09:18 AM
PE,

You don't have any objections if I keep at it until someone gets it right, do you :) ?

Bob

Photo Engineer
05-02-2007, 09:41 AM
I'll probably give the answer before then.

PE

Photo Engineer
05-06-2007, 02:07 PM
Here goes with the answers:

1. The use of Egg Albumen was certainly a hint. It was proved by the fact that there was no additional use of sulfur to sensitze the emulsion. Gelatins before about 1950 were active gelatins that added sulfur sensitization during the making process. These gelatins were used in the same era when egg albumen was commonly used. But the use of Albuemn by itslef was not proof as many still use it today for the surface characteristics it can add to a coating.

2. The use of Magnesium Oxide or Magnesia in any formula is a hint that the formula is old. Early emulsions used non-deionized gelatin and the pH varied all over the place. Formulas added Magnesia in varying amounts (or a standard amount if your gelatin was consistant) to adjust the acidity of the gelatin. This was put in before the wash as it was usually washed away by the next step. You will see this in very old formulas as "Alkali balance or Acid balance, add Magnesia solution to balance the acid content of the gelatin as needed". That is approximately the way it appears in several old formulas that I have dating from the 30s and 40s.

3. Salted gelatin ISO wash. Adding Sodium, Calcium or Magnesium salts particularly the Sulfate as we see here, was an early and imperfect method of washing emulsions. When PA gelatin (phthalated) became common, this method was abandoned.

So, those were 3 hints to me, along with the unknown solution which is virtually impssible to decipher unless the destription is given somewhere in Steigman's work. I doubt Grant would leave it out if published, and if not published then it was a secret 'magic elixir' added to adjust the contrast. I have not looked it up and have not bothered Grant for more information.

PE

ben-s
05-06-2007, 06:29 PM
haha. So I was Waaaaay off then!
Thanks for ending the suspense anyway.
It seems like speaking another language, with tiny little hints scattered around.

rmazzullo
05-15-2007, 11:01 PM
So, those were 3 hints to me, along with the unknown solution which is virtually impssible to decipher unless the destription is given somewhere in Steigman's work. I doubt Grant would leave it out if published, and if not published then it was a secret 'magic elixir' added to adjust the contrast. I have not looked it up and have not bothered Grant for more information.

PE

Hello PE,

Just out of curiosity, I entered "Rr340" into the Google patent search, and it popped up in patent number 2930693, where a "Rr340" is listed as a "green sensitizing dyestuff". Could this definition of "Rr340" be a possible fit as used in this formula?

Thanks,

Bob M.

Photo Engineer
05-16-2007, 09:33 AM
Bob;

Yes, it might be. This is not a Kodak designation for a green sensitzing dye though. In fact, it is not a Kodak designation for any dye at all AFAIK. Therefore, if used by Grant it would be from a patent, old document or by private communication.

The actual structure may be unknown to us then unless you can get the BIOS report referred to in the patent. For those of you unfamiliar with the BIOS reports, these are the disclosed AGFA formulas published at the end of WWII. The formula is stated in the patent to appear in report 1355 page 86.

Under the circumstances, any green sensitizing dye might work, but I'm not familiar with the need to spectrally sensitize lith emulsions.

PE