Hummm...
I did say
"putting aside the possbility of physical development for the moment".
Are you saying that with normal chemical development...
you can develope a latent image... with out the presence of the silver halide?
???
Microdol-x replacement
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Hummm...
I did say
"putting aside the possbility of physical development for the moment".
Are you saying that with normal chemical development...
you can develope a latent image... with out the presence of the silver halide?
???
Without the patents in front of me I am only able to wonder, how, without relying on physical development) it would be possible to "develop" a latent image into a proper silver image... unless you replace the silver halide with some other silver compound... but then thats cheating.
Your point, however,
that the latent image is silver and not silver halide goes without saying.
When would I want a developer to do this, and what benefit would it be?
Bill, my notes & reference books are rather scattered at present, most are in storage here in the UK, a few in Turkey, so I'll have to go by memory.
One that springs instantly to mind though is a Maco/Rollei developer for their R3 film RLC, other developers I'm thinking of may well have gone out of production over the last 5-10 years and I think only one used Ammonium Chloride.
Chlorides both Ammonium & Sodium do appear in post war patents for fine grain developers, X-ray and Colour developers, also surprisingly in speed enhancing developers but it's fair to say that Chlorides really aren't that common in Developer formulae. Microdol-X and Perceptol are the two major exceptions.
Ian
Ray, Kirk;
The patents refer to catalyic development. The latent image is silver metal to star with. Adding an oxidant to the developer which adsorbs to the silver surface (latent image) will result in oxidation of developer and formation of any desired dye image. The two common agents are hydrogen peroxide and cobalt hexammine chloride. I have taken an ISO 400 color film latent image and amplified it to full speed and beyond.
I have also reduced silver levels to about 0.1 of normal and gotten normal images. It is also possible to coat the cobalt complex in the coating. See the patents is all I can say.
PE
The patents refer to catalyic development. The latent image is silver metal to star with. Adding an oxidant to the developer which adsorbs to the silver surface (latent image) will result in oxidation of developer and formation of any desired dye image. The two common agents are hydrogen peroxide and cobalt hexammine chloride. I have taken an ISO 400 color film latent image and amplified it to full speed and beyond.
I have also reduced silver levels to about 0.1 of normal and gotten normal images. It is also possible to coat the cobalt complex in the coating. See the patents is all I can say.
PE
R.L.C. = Rollei Low Contrast which is a low contrast document developer (by Udo Raffay).
R.L.S. = Rollei Low Speed (equivalent to CG512) is an ultra fine grain depth developer (24 degrees C.) , also from Raffay but this one is very suitable for the R3 film.
The R.H.S. = Rollei High Speed came from Amaloco Photochemicals, AM74 an all round Phenidone/Hydroqiunon developer. Very populair in the BeNeLux countries and Germany. Jaap van Beugen (Amaloco) made this one in 1974. AM74 and some main B&W products are produced again under licence in Germany up from this month. The chemical plant in Ommen (the Netherlands) closed last year August.
The receiptures from Raffay are produced by Mr. Saban Suvatlar in Germany either. And for sure there is an connection to Rollei-Maco.
R.L.S. = Rollei Low Speed (equivalent to CG512) is an ultra fine grain depth developer (24 degrees C.) , also from Raffay but this one is very suitable for the R3 film.
The R.H.S. = Rollei High Speed came from Amaloco Photochemicals, AM74 an all round Phenidone/Hydroqiunon developer. Very populair in the BeNeLux countries and Germany. Jaap van Beugen (Amaloco) made this one in 1974. AM74 and some main B&W products are produced again under licence in Germany up from this month. The chemical plant in Ommen (the Netherlands) closed last year August.
The receiptures from Raffay are produced by Mr. Saban Suvatlar in Germany either. And for sure there is an connection to Rollei-Maco.
@ Robert: I bought a bottle of CG512 from Mr. Suvatlar. Is 24°C an obligation, or just to reduce the (rather long) developing times?
You are running into very long developing times. CG512/RLS is excelent in a Jobo CPA/CPE/CPP system.
Here is the CG512/RLS developing table (valid for 24 degrees C):
Dead Link Removed
Best regards,
Robert
Here is the CG512/RLS developing table (valid for 24 degrees C):
Dead Link Removed
Best regards,
Robert
I don't mind long developing times... and I have no Jobo processor! What would be the percentage for 20°C (small tank or tray for sheet films)?
Well a 20 minutes development (24 degrees C.) would go to 28 minutes (20 degrees C.) and the question is that over 30 minutes the developer is still stable and not oxydised. Maybe a good point asking for Mr. Suvatlar what exactly are the limitations of this developer.
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Ian, and subsequently RobertV, thank you very much for the references to modern developers with ammonium chloride. I have been studying these. I was also very surprised to find thiocyanate being used in the manner of DK-20. One of the great weaknesses of FDC, as I mentioned earlier in this thread, is that it does not address the photochemical work being done in Europe, particularly Germany. I knew this was a problem from the start, but frankly, I thought I was doing enough internationalization by giving Crawley's work the attention it deserves, which had never been done by an American writer before or, for that matter, a British writer. Regardless, it has been a great pleasure to look at the ingenious formulas from Rollei and Spur, apparently by Raffay, that have adapted some of these old-fashioned solvents for use with modern materials. It is not how I would do it, and I think there are better chemicals to use, but I am still very impressed.
Ron - - re Henn's beard, he only grew it after he retired. He told me it caused a lot of raised eyebrows in Rochester. Not to mention his becoming a painter. Quite a lifestyle change!
In the early 1960s when Crawley was writing his little masterpiece for the BJ, the gold standard for evaluating a developer's proclivity to dichroic fog was Royal-X, the then-fastest, coarsest-grained film available. What film, today, is the most sensitive to solvents?
Ron - - re Henn's beard, he only grew it after he retired. He told me it caused a lot of raised eyebrows in Rochester. Not to mention his becoming a painter. Quite a lifestyle change!
In the early 1960s when Crawley was writing his little masterpiece for the BJ, the gold standard for evaluating a developer's proclivity to dichroic fog was Royal-X, the then-fastest, coarsest-grained film available. What film, today, is the most sensitive to solvents?
Bill,
Did I lose? :confused:
I was kinda looking forward to a signed copy of your book...
since I dont have one yet...
but I could settle for a copy of those notes!
(naturally- for my eyes only)
???
Bill, you have hit the nail on the head with regards to why I disagree with many statements in the FDC, coming from an entirely European background I see the quite different approaches by companies like Ilford, Agfa etc.
Interestingly you say in the FDC many of Ilford's early developers (pre Phenidone) are clones/generic, I'd actually say that until the mid 30's so were Kodaks. Even the venerated "D76" is supposedly a reworking/derivative of the earlier Wellington & Ward MQ Borax Fine Grain developer, other Kodak developers come from companies they took over & absorbed, Velox, Wratten & Wainwright etc etc.
It has to be remembered that the first (Ilford) Manual of Photography (with formulae) was published in 1890 two years before the founding of Eastman Kodak and George Eastman always regarded Ilford extremely highly proposing a merger or take over in 1897 and again in 1903.
There may be a connection between Ilford or Johnsons and the MCM (Miniature Camera Magazine) formulae, one of the contributors was Henry Russell, he wrote a column under a pseudo-name "Minicam" as well as under his own name. It's more than a co-incidence that his own company were responsible for the advertising for Ilford and Johnsons. There was also some inter-trading between Ilford & Johnsons - I have an unopened bottle of Ilford Limited "Amidol - Johnson's" sat in front of me as I write.
You may also be unaware of the links between Crawley, Paterson & Ilford. Ilford used to manufacture Paterson's chemistry for them to Crawley's formulae, I had a very interesting discussion about this in the early 80's with one of the chemists who had been involved, by then Paterson chemistry was made elsewhere.
Ian
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Bill, after reading through this thread (twice) I think it's a meaningful question you ask. As a small format shooter (35mm/6x8cm) I've become interested and have been hitting the books to learn more. Will this be a subject for a chapter in your new book?
As I indicated in a previous post, I'm interested in exploring what NH4Cl does with modern films, but "I'm new at this". My interest isn't really in 35mm film but the 6x8 sheet films I have on hand in my freezer - to sacrifice in the name of science - are as follows:
TRI-X (TXT 4164), thick base - discontinued format
T-MAX 100 (4052), thick base
efke 100
efke 25
Also:
TRI-X 320, 120 roll film
PLUS-X 125, 120 roll film
I'll be mixing chemistry from scratch and staying with the more basic formulas, and think the thinner base efke 25 or 100/ID-11 combination may be the most interesting for starters. Any advice offered will be appreciated. I'm sure I'll have questions later.
I love science experiments!
Regards,
Paul
PS. I'm glad you two professionals, you and Ian Grant, are discussing together, it make it all more interesting, informative, and deeply insightful, for me. The same goes for comments by Ron (PE). Thanks, to you all.
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A good substitute easy formula for Microdol-X:
Metol 7.5 gr
Sodium Sulfite 100.0 gr
Sodium Bisulfite 7.5 gr
Water 750 cc
Water-to-make 1000 cc
Working solution: 1:3 or straight
Developing time: 9’ to 11’
It is balanced to produce lower grainess and higher sharpness than normal developers with very little loss in effective film speed. In common with some others fine-grain developers, it tends to produce an image of slightly brownish tone, which gives more printing contrast than is apparent to the eye.
Metol 7.5 gr
Sodium Sulfite 100.0 gr
Sodium Bisulfite 7.5 gr
Water 750 cc
Water-to-make 1000 cc
Working solution: 1:3 or straight
Developing time: 9’ to 11’
It is balanced to produce lower grainess and higher sharpness than normal developers with very little loss in effective film speed. In common with some others fine-grain developers, it tends to produce an image of slightly brownish tone, which gives more printing contrast than is apparent to the eye.
Did you read the whole thread? If you didn't, you should. I found it most interesting. Much of the talk is about adding chlorides to developer formulas. There's a note in The Darkroom Cookbook about D-25 that states: "If it is not essential to obtain minimum graininess use half the quantity of sodium bisulfite". That would be the formula you're giving.
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Also the same formula I've mentioned. See my post
163 this thread. I've included the source. Dan
Sorry
I got it from "150 do-it-yourself Black and white popular photographic formulas" p.27
same book as yours except for the edition. This is a 1977. The frormula is the same. My apologies.
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Sorry
Don't worry, some of these threads are so long and complex, it's easy to miss something.
No need to apologize, your post was informative. You probably know more than me.
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Paul, we'll all be following your experiments with great interest. If, if, if, conventional wisdom is correct, then you probably will only see problems with Tri-X and perhaps Plus-X. (One of the few times I can remember producing dichroic fog was with FX-2 used for several hours as a stand developer. I don't remember what the film was but it would have been a medium to slow film. It may have been Agfa Superpan, a low-cost so-called 'kiosk' film that I liked very much and worked with a lot.)
If I were going to experiment with super-fine-grain developers, I would choose to work with the ppd derivatives, because I think there is a better chance of getting interesting edge and gradation effects to happen. But I don't want to discourage you from working with ammonium chloride, because anything we learn about the way it works with modern films will be of great interest.
Ron could comment better on precautions to take. I would imagine it was important to have a good, fresh, well-maintained source of the chloride, and that one probably shouldn't keep the solutions at all long.
What if the results are promising but not sharp enough? I would consider using a water rinse instead of a stop bath, hoping to gain some edge effects. But to start with, I would use a stop bath, because that would be keeping at least one variable out of the way.
Good luck!
If I were going to experiment with super-fine-grain developers, I would choose to work with the ppd derivatives, because I think there is a better chance of getting interesting edge and gradation effects to happen. But I don't want to discourage you from working with ammonium chloride, because anything we learn about the way it works with modern films will be of great interest.
Ron could comment better on precautions to take. I would imagine it was important to have a good, fresh, well-maintained source of the chloride, and that one probably shouldn't keep the solutions at all long.
What if the results are promising but not sharp enough? I would consider using a water rinse instead of a stop bath, hoping to gain some edge effects. But to start with, I would use a stop bath, because that would be keeping at least one variable out of the way.
Good luck!
Well, here are some thoughts.
1. Add the ammonium bromide last just before use due to the volatility. That will remove a potential variable.
2. Check solution temperature just before use. Ammoniium Bromide will cause the developer to chill off. The temperature drop may be large depending on the amount used.
3. Use a standard developer with and without Ammonium Bromide just to have a reference.
Thats about all I can add.
PE
1. Add the ammonium bromide last just before use due to the volatility. That will remove a potential variable.
2. Check solution temperature just before use. Ammoniium Bromide will cause the developer to chill off. The temperature drop may be large depending on the amount used.
3. Use a standard developer with and without Ammonium Bromide just to have a reference.
Thats about all I can add.
PE
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