Newbie Silver Chloride emulsion, way to go?

VesaL

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Hello everyone related, I have been looking thru various websites how to make AZO type / Silver Chloride Emulsion. As formulas differ in addition rates and ripening, i pieced this kind of formula from all the data but not sure will it totally go wrong? (you never know until you try it, I know :0)

Part A
150 cc distilled water
2.25 g Potassium Chloride
7.5 g Gelatin

Part B
25 g distilled water
5 g Silver Nitrate

Part C
14 g Gelatin

-Warm part A & B to 45C under waterbath.
-Add part B to part A over 20 min, keeping temp to 45C, constantly stirring.
-After 20 min, add part C and raise the temperature to 55-60C, keep 25 min. constantly stirring.
-After 25 min, let to cool slowly, while constantly stirring.
-Chill, noodle, wash to get rid of unwanted chemicals.

What I'm trying to archieve is emulsion with long tonal scale (like in albumen process) for to be used in digital negatives. Emulsion speed is not crucial to me, but i would like to get good gradation and low fog emulsion. If anyone has something to add or laugh upon it, all comments would be more than welcome.

Many thanks in advance,
Sean
 

dwross

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Without making the emulsion, it's hard for anyone to make precise comments on it, but nothing jumps out at me as laughable . Two points, though. A chloride emulsion is inherently contrasty, even the way your emulsion sets it up. If you want a long scale, go with a bromide emulsion. Also, a paper emulsion doesn't have to be washed. Save yourself the step. Having said that, I know that a great deal of the fun of emulsion making is designing and using your own emulsions! If you are planning on making digital negatives, you can finesse the tonal scale of the negative to match any paper, including yours (if it works). If you make a low contrast digital negative, you could print it on standard Azo-type paper, which is easier to make than your version.

However, if you want to start with a proven bromide recipe, I can recommend the emulsion on p.120 of my book. http://www.blurb.com/b/6465389-the-light-farm. I designed it for a very long tonal scale. More info on chloride papers and matching negatives on p.112.

Lots of possibilities. This is by no means a one-size-fits-all game! Best of luck and fun.
 
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VesaL

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Thank you, your book is definetely worth checking out. If I get this right, and matter that confuses me is that AZO -type paper is based on SilverChloride emulsion, and praised by some having long gradation, right?

So if I make Silver Chloride emulsion, with slow addition rate for Ag, should then (in theory) make longer gradation albeit larger grains?
 

Photo Engineer

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I have duplicated the Azo emulsion in my book. After reading your formula, I can say that there is too little gelatin in the kettle to start with, and the addition rate is too slow. I use 1 minute. I agree with Denise, the wash is not needed.

A good Azo paper should give a grade 2 when the emulsion is at the proper dilution, done with 10% gelatin.

PE
 

dwross

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I suppose it depends on how long a tonal scale you need. That is, what kind of negative will you be using? An Azo-type paper is unlikely to ever have as long a scale as albumen; nor should it. It is a very beautiful paper, though. Best of match your negatives to a paper you love than the other way around (personal opinion alert!)
 

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Azo grade 2 paper met an ANSI standard for paper contrast grades and thus matched papers such as Kodabromide and Medalist. They differ in the toe and shoulder and Dmax. Denise is correct. You may want a grade 3 or a grade 1. Your formula would make more of a grade 1 but that is a guess only. I have never made one like you describe.

PE
 
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VesaL

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Thank you PE and Denise, I really appreciate your positive and highly informative input. Will I want grade 1 or grade 3 is good question. I could reverese the order in amount of gelatin between A and C, and double the addition rate so it would be 10 minutes. I understand that Silver Chloride type emulsion may not compete with gradation what comes to Albumen, but Albumen print so far has only satisfied the gradation range what comes to my digital negatives as I have been unable to match my digital negatives with modern silver gelatin papers.

As I'm originating from analog darkroom too, and frustrated with too much variables and too long exposure times with Albumen printing along with highlight yellowing etc. so i was thinking that Silver Chloride would be close match to fine-tune the negative. (And I'm fan of Edward Weston ;0)
 
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Photo Engineer

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I have made digital negatives from 35 mm color and 4x5 B&W analog originals and have contact printed them on 8x10 sheets of my version of grade 2 Azo. Many people think that the results are quite good.

Straight prints onto this Azo type paper have gotten good reviews as well.

PE
 
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VesaL

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PE, is it possible to purchase your AZO recipe..? I understood from your previous post that it is included in your Book, but at this time (and money constrains) I would be keen interested in just the AZO recipe. PM if you are interested, many thanks.
 

Photo Engineer

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That is not a problem. It is virtually the same as your formula but using 10% gelatin at the start, no C solution, and 1 minute addition at 60C with a 10 minute hold. Give that a try or use one of the formulas on Denise's web site. The formula varies wherever you make it, and Denise had to adjust the formula a bit for her conditions. I'm sure that you will have no problem.

I'll look one up though if you want more exact figures.

PE
 
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VesaL

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Many thanks PE, I will give it a shot upon your suggestions. Still waiting the postman to bring me the Silver Nitrate that I ordered couple days ago, other than that the lab is ready for spin. I will post some examples later. Many thanks once again.

-Sean
 
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VesaL

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I just got back from my basement darkroom with some tests to my silver-chloride emulsion. It does "work" and no fogging visible so i must have done something right. However, the contrast is excessive just as I were afraid of and like you mentioned. Maybe tripling the digestion/ripening time would make grade 1-2 emulsion..? Now it's in grade ballpark 4-5. But boy it sure was fun to see the latent stouffer 31-step tablet emerge :0)

When the dmax was reached using stouffer step tablet as a guide, it only reached to step 10 (step 10 had faint trace.)

-Vesa
 
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VesaL

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Many Thanks PE,
I will try your suggestion tomorrow.

-Vesa
 

ay1

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Do ou have that formula? I want to make some Azo type with a long range.
 

Svenedin

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Why are you even doing this for an electric negative?
 

removed account4

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Svenedin said:
I think I have misunderstood.
Click to expand...
sorry if i misunderstood you ... i was thinking electric negative meant digital negative ?
and you were questioning why anyone would make their own emulsion
( which i equate with doing anything alternative process ?! ) for a digital / electric negative ..

maybe i misunderstood you ?
sorry if i did, i figured you were questioning the validity of using a hybrid negative
and why it might ( or might not ) be worth the trouble of making home made emulsion to print on ...

ive printed digital ( read xerox paper ) negatives with home made photo emulsion negatives
as well as cyanotype negatives, i got great results ...
the emulsions i have brewed and done this with were made with sodium chloride, potassium bromide gelatin and water
one i also added an extremely dilute amount of dektol ...
got fantastic results ... ( still have the latter, haven't had a huge amount of time to coat and use it )
its fun ... isn't that what the point is ?

thanks !

john
 
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