Lith emulsion from Haist (Steigman)
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.
Water 425 ml
Conc HCl (hydrochloric acid) 2 ml
Cadmium Chloride, CdCl2.2H2O 0.4g
Gelatin 20 g
Egg Albument 10% 2 - 3 ml
Water 100 ml
Silver Nitrate 20 g
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.
Originally Posted by Photo Engineer
Once again, you dangle tantalizing puzzles and inspiration to work/play/learn in the darkroom. You're a treasure.
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....)
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.
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.
I'm game. I'll take a swing at embarrassing myself. Old, because of the addition of egg white for the sulfur??
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You have to get both. You didn't even get one. You were close, kinda.
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.
grammar puzzle: can you spot the typo (or as a friend more honestly calls them: "thinkos" ?
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...?