Peter Schrager
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Thiourea, even though it has a long history with toning, is a chemical I try to avoid. It has a Contact Rating: 3 - Severe (Life). It is anticipated to be a carcinogen - in response to that the State of California has declared it to be carcinogenic.
Probably best to avoid the use of it if you can.
IThiourea, as well as urea are metabolic byproducts of a lot of plants and animals.
What I love about TF-3 is being able to selenium tone test strips and work prints without having to wash after an acid fix, then re-fixing in plain hypo.
Ammonium Hypo solution 200 ml/l
Sodium Sulfite (anh) 10 g/l
Ammonium Thiocyanate 10 g/l
Thiourea 10 g/l
As mixed the pH was 7.8 at 22.3 deg C. I adjusted it to 6.6 at 22.6
deg C with about 12 ml of 28% acetic acid. As mixed, it has a faint
ammonia odor, but after the pH is adjusted, it has no odor of
ammonia. The pH range of this fix should be about 6.3 - 6.7.
Dan-that formula is strictly for papers....one pound of thiosulfate;
15 grams of sulfite and 64 oz. water....thank you for the TF2
formula and it is not in the cookbook; at least the older
edition Thanks, Peter
That is, AFAIK, an earlier version, namely SFI. I did not post it BTW. It was posted by another member who copied it from a very extensive thread on Photo Net. I am up to SFVII which has met the goal of duplicating the results of SFI, but with reduced wash times and better chemistry.
PE
That is, AFAIK, an earlier version, namely SFI. I did not post it BTW. It was posted by another member who copied it from a very extensive thread on Photo Net. I am up to SFVII which has met the goal of duplicating the results of SFI, but with reduced wash times and better chemistry.
PE
By Photo Engineer - 10:23 PM, 02-01-2006 Rating: None
I am now up to Super Fix VII.
Is there a formula for SFVII? If not, is somebody going to sell it?..Evan Clarke
The formula posting has the ID title:
superfix
unregistered (10-31-06)
The dating of the other posts appear to be in error as they are all dated prior to Sean's update of the articles.
I have never posted any formula but SFI and have only referred to my ongoing work. Several individuals have samples of SFVIII. The formula will not be published.
PE
No published findings that I know of except for the work
by Haist and work I did at EK which is for the main part
unpublished. I can back up most of the assertions on
alkaline and neutral fixes as well from work
I have personally done. As pH goes up, swell goes up
(with bone gelatin) and washing becomes easier. PE
All I can do is try to pass it on.
PE
What is that saying about teaching a person to fish?
I am not sure I understand why you don't post your "in house" testing procedure and then share your results.
Perhaps you needn't prove anything...
The one thing we need more than new unpublished formulas with limited testing and a doubtful future is sound training in basic photographic processing research and product development... If you have something to teach... as time passes us by - that will become the more valuable in the long run. (IMHO)
I am sure many may be content to just buy the most recent product inexpensivly, and that IS fine.
However, (I may be wrong!) but I think the most valuable lesson we will ever be able to learn from you is how to think like a Kodak researcher. Strange, but I feel that Kodak research was somehow better than the Kodak products that evolved from it.
Perhaps that doesn't make any sense.
Well, anyway, nice friuts are fine,
but a working knowledge of agriculture is incomparable.
Ray
However, (I may be wrong!) but I think the most valuable lesson we will ever be able to learn from you is how to think like a Kodak researcher.
I don't want to minimize the way that "Kodak researchers" think, but I'll say that learning how any science researcher thinks will be a benefit.
Ray;
I have posted both my fixing test procedure and my developer stability and quality test procedure, the latter with results. If you wish, I will re-do this if you really feel it is necessary. Sorry you missed it elsewhere.
As for published works on fixing and washing, I have found quite a bit in Mees and James and Mason. There is quite a bit in Mason, especially on washing which I have quoted elsewhere.
But, basically to summarize, a fixer can be easily tested with 3 solutions.
1. Silver Nitrate in Acetic Acid - Hypo retention test
2. Sodium Sulfide in water - Silver Halide retention test
3. Potassium Iodide in water - Fixer exhaustion test
Instructions are supplied with kits sold by major suppliers of photochemicals. Testing is simply seeing how well a fixer performs in a given sequence of fix time, dilution and wash.
PE
Ray;
I have posted both my fixing test procedure and my developer stability and quality test procedure, the latter with results. If you wish, I will re-do this if you really feel it is necessary. Sorry you missed it elsewhere.
...to summarize, a fixer can be easily tested with 3 solutions.
1. Silver Nitrate in Acetic Acid - Hypo retention test
2. Sodium Sulfide in water - Silver Halide retention test
3. Potassium Iodide in water - Fixer exhaustion test
Instructions are supplied with kits sold by major suppliers of photochemicals. Testing is simply seeing how well a fixer performs in a given sequence of fix time, dilution and wash.
PE
...the men and women doing all that research at Kodak were taught and learned science first, then they worked for Kodak doing research.
I don't want to minimize the way that "Kodak researchers" think, but I'll say that learning how any science researcher thinks will be a benefit.
Ray;
I am not permitted to refer to or post these tests, as I am involved in the sale of such products. Anything more than these comments is a clear conflict of interest in the opinion of some APUG members.PE
Now, the question of going to SFVII or SFVIII from SFI is... I didn't know yet exactly what the changes had to be. I had to creep up on them incrementally by using prior experience. PE
By cut corners, I think in post 39 you wrote:As for cutting corners. No, I do not. I wish I could, but then I could not face anyone and tell them that the product was good. Sorry.
PE
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