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albada
12-04-2011, 08:39 PM
A second experiment done this afternoon makes me suspect that the Instant Mytol formula is incorrect. I created a small 50 ml working solution (not concentrate) with the correct proportions of all ingredients except that I omitted Phenidone. I simultaneously dipped pH test-strips into this test-solution and fresh XTOL, and compared their colors with each other and with the color-charts. I did this with two brands of pH-strips. Both showed XTOL at 8.0 and the test-solution at 8.7. These numbers are approximate, but the conclusion is clear: The pH of Instant Mytol is too high.

I'll reduce the TEA in Instant Mytol to get the pH correct (matching colors with XTOL). Or maybe I'll skip this stepping-stone and move onto modifying this formula to mimic DS-10. Let's see, DS-10, that was the goal of all this, wasn't it? :)

Jerry, like you, I don't shoot that much, maybe a roll a month. And some of that is C-41. So the desire is for a developer that gives XTOL-quality but that keeps a long time, and is tolerably convenient. Mixing two things such as concentrate and sulfite is fine, but having to mix everything from scratch just to dev one roll is too much effort.

PE: Thanks for the warning about Ammonium bromide and fog. I've entered that into my file of chemistry notes. You have an enormous amount of knowledge of tidbits like this, not to mention principles of operation for all kinds of processes. Have you considering putting all this into a book? If so, sign me up to buy a copy!

Mark Overton

Photo Engineer
12-04-2011, 09:01 PM
Mark;

Right now I am in the final stages of writing the Photographic Emulsion Making and Coating book. Bill Troop and I have discussed writing what you say and there are some interviews on tape with Scott Sheppard on this topic somewhere. Unfortunately, the book you envision will take several years to produce and cost a bit. Also we need to get rights to portions of Anchell and Troop to kick start the project.

PE

Gerald C Koch
12-04-2011, 09:26 PM
Ron I would say give it a try. Since there would be much more ammonium sulfite and hence more ammonia I would do it outside. I sometimes miss having a hood. Jerry

albada
12-07-2011, 05:31 PM
So far, my experiments show that about 6.8 ml/L is the correct amount of TEA to add to Instant Mytol to hit the target pH of 8.2, instead of the 13.4 ml/L given in the formula.

Question 1: What alkalis will dissolve in propylene glycol?
Obviously TEA will, as will borax. Sodium carbonate contains carbon, so perhaps it'll dissolve also? I don't have much hope for sodium metaborate, but I'll have to check whether it's considered organic. Other alkalis? I'd like to experiment with the effects of alkalis on image-quality. The grain from TEA looks rougher than I like.

Question 2: What halide-solvents will dissolve in propylene glycol?
Sodium chloride or ammonium chloride? I suspect PPD will, but its toxicity concerns me, and it's a developer also.
It would be convenient to not have to dissolve sodium sulfite separately from the concentrate.

Thanks,

Mark Overton

Gerald C Koch
12-07-2011, 05:37 PM
Most inorganic compounds will not dissove in glycols. You are really restricted to using an amine TEA, DEA, or MEA and a few others. Kodak uses sulfur dioxide adduct as a halide solvent and preservstive in HC-110.

jnanian
12-07-2011, 06:10 PM
Thanks for the suggestion. Coincidentally, the TEA arrived in the mail today, so you can guess what I'll be doing this weekend. :)
A few postings in apug.org have noted that PC-TEA is a little grainier than XTOL, probably due to having no solvent in the soup. Adding Sodium Sulfite creates Jordan's "Instant Mytol", described here: http://www.apug.org/forums/forum223/33880-instant-mytol.html
So I'm thinking of trying some of that Instant Mytol.

Mark Overton

hi mark

why don't you contact ryuji himself ( he has a website and is accessible )
rather than ask people who may or may not have any idea of what his changes might have been ?

good luck !

albada
12-08-2011, 10:36 AM
Gerry: I was afraid of that. PG is a good carrier (I guess that's a good word for it) because oxidation isn't a problem, but few things will dissolve in it.

Jnanian: That's a good idea! It hadn't occurred to me to contact Ryuji. It's winter, so his freelance photo business is probably slow now, and maybe he'll have time to talk about his work. BTW, did he simply lose interest in film? It seems he hasn't posted in a few years now.

Anyway, I'll be shooting a roll of Tri-X today at a company-luncheon. The camera will be a Minolta V2. Gotta love those classic cameras.

Mark Overton

jnanian
12-08-2011, 12:14 PM
Gerry: I was afraid of that. PG is a good carrier (I guess that's a good word for it) because oxidation isn't a problem, but few things will dissolve in it.

Jnanian: That's a good idea! It hadn't occurred to me to contact Ryuji. It's winter, so his freelance photo business is probably slow now, and maybe he'll have time to talk about his work. BTW, did he simply lose interest in film? It seems he hasn't posted in a few years now.

Anyway, I'll be shooting a roll of Tri-X today at a company-luncheon. The camera will be a Minolta V2. Gotta love those classic cameras.

Mark Overton

hi mark

i am not sure if he lost interest in film or traditional photography: i doubt it.
he not only was involved with creating photochemistry, but he also
was very involved in making photo emulsions.

you can probably look up his threads / posts when he was here
to see what was going on " politically " when he was here ...

good luck !
john

Ryuji
12-10-2011, 01:35 AM
All right Mark, your email got me curious and googled and found this. It's kinda surprising I remembered the login u and pw.

First, I recommend you to get a better way to measure pH than test strips. You'll notice that pH difference of 0.2 would make a significant difference in the development time required to attain a target contrast index.

Triethanolamine is a good alkaline agent in fine grain developers. If you are making an accutance developer or more rapid action developer, you can mix diethanolamine as well. Some of the derivatives of TEA and DEA are also good alkaline agents (some names were given in my old posts - please find them). You can get a range of buffering systems with them. But, if you are a casual darkroom hobbyist, don't go there.

Borax is a really good buffer for pH 9 range, but not really for 8 or 10. It's easy to use, and cheap, but that's about it.

Small quantity of ammonium salt would probably do little harm at pH of 8.2. But I'd rather not use them, unless you know what it affects and carefully control for it. I recall trying using ammonia in small quantities, but I vaguely recall the results varied a lot depending on the film. That was actually somewhat expected. Also, I'd definitely not use ammonium salt in developers of pH any higher than that.

I actually have an improved version of fine grain developer as well as high accutance developer, but never commercialized.

Regarding the silver halide complexing agent for fine grain effects, I also played around with a few pyrimidine derivatives. Some are interesting because they are also a very mild developing agent when used alone. But after all, sulfite was easier to use and a lot cheaper.

Another thing I never posted before is that I have a developer stabilizing additive. This actually improves the shelf life and tray life of the developers. It was used in print developers that had silvergrain label and sold in F-style jugs but not any other bottle shape or label. This thing actually works well in film dev as well, but the additive looks brown color and a lot of users would get confused with the color of stale developers. So that was another concern for me and I didn't want to go ahead without a colorless stabilizer additive. But I was using it for routine processing in my lab.

Another challenge is that if you try to make a highly concentrated film developer (as I was doing) you'll sooner or later face a problem with phase separation. Some of the compounds in the concentrated developers do not mix with water rich of inorganic salts. So, you'll get sulfite-rich water phase and "oily" look phase containing amines, Dimezone S, etc. There are some solvents you can use to blend them, but they're not particularly safe. Certainly not the kind of stuff I'd put in if I were to sell the product as low toxicity. Well, that was a part of the reasons why I was looking for something to partially replace sulfite with.

Alright, I think I shouldn't write much more frmo memory - any more would risk being incorrect.

Ryuji
12-10-2011, 02:04 AM
Saying that a formula has too many ingredients is like saying that Mozart's music has too many notes. :)

Good quotable statement.

Ryuji
12-10-2011, 02:05 AM
I wonder what a little bit of EDTA-Na would do for stability.

If you are talking about DS-10, don't. You add a little EDTA, and the keeping property worsens. You add a LOT, and it gets a little bit better. It's not a matter of stability constants. It's something else. If it were that simple it would be all solved back then.

Ryuji
12-10-2011, 02:11 AM
As I stated before EDTA cannot be used since it actually catalyses the Fenton reaction. Don't know about NTA. This was the problem that Ryuji encountered. Which agents can be used and which cannot.

That is correct. I am not 100% sure if it is Fenton reaction per se, or something like that but different. But frmo the macroscopic systems view, it is the same problem.

The outcome should be somewhat predicted from the redox properties of the chelated iron complex. The goal is to keep the chelated ferrous ion in the form not readily oxidized. An alternate approach would be go bind iron to some bulky molecules so that any reaction it engages in will be slowed down.

Gerald C Koch
12-10-2011, 11:57 AM
The outcome should be somewhat predicted from the redox properties of the chelated iron complex. The goal is to keep the chelated ferrous ion in the form not readily oxidized.

Hi Ryuji,

Good to see you again on APUG. I tried unsuccessfully a few weeks ago to get such information for iron chelates. Lots of information but not what I wanted.

Jerry

Photo Engineer
12-10-2011, 12:09 PM
Jerry;

Try the DEQUEST series of chelating agents. They have one of the highest complexation constants with Iron of any such agent. It is so strong it can redissolve Ferric and Ferrous hydroxide and that is saying a lont.

PE

albada
12-10-2011, 02:50 PM
Hi Ryuji,
Good to see you again on APUG. I tried unsuccessfully a few weeks ago to get such information for iron chelates. Lots of information but not what I wanted.
Jerry

Yes! I hope you stay and continue to contribute.
I am new to developer-chemistry, but I've read many of your past postings, and value your knowledge.

Mark Overton

Ryuji
12-10-2011, 04:12 PM
I tried unsuccessfully a few weeks ago to get such information for iron chelates. Lots of information but not what I wanted.

That sounds right. I couldn't find that data tabulated anywhere back then using traditional as well as electronic libraries at MIT and Harvard. Met a bunch of industrial chemists, electrochemists, ..., no one had idea of where to look. That's why I started doing own experimentation to find some empirical laws that could guide me in finding the right compound. Meanwhile, a list of chelating agents that don't help or worsen the oxidation problem grew. A lot of people threw names of their favorite chelating agents at me but they had no idea. There is no one universal scale by which usefulness of chelating agents can be measured, for this particular problem.

albada
12-10-2011, 11:47 PM
First, I recommend you to get a better way to measure pH than test strips.


I thought I was being clever by matching the color against XTOL. I put two strips into the test-developer and fresh XTOL at the same time, and compared. When colors match, pH should be equal. Not so! A liquid indicator gave a large mismatch when the strips agreed. And when the strips agreed, activity was lower than expected. Now I distrust the strips. Time to buy a pH meter! I'm planning to get a Hanna pHep-5.



Another challenge is that if you try to make a highly concentrated film developer (as I was doing) you'll sooner or later face a problem with phase separation.


A google search just told me what "phase separation" is. That problem never occurred to me.

Here's an idea: Can we make a dual concentrate? That is, have two concentrated solutions, one using propylene glycol, and the other using water. The developers would go in the PG (as with PC-Glycol), and everything else in the water-based concentrate. I think the big problem here is that it's not possible to concentrate sodium sulfite enough due to its solubility limit. So we must find another more powerful halide-solvent. Perhaps ammonium chloride? Anyway, I wouldn't mind mixing two concentrates 1+1+10 or similar, as long as both concentrates would last years.

Another idea: Mix in the (powdered) sodium sulfite separately. Then add the concentrate. That would solve the sulfite-problem nicely. Comments on these ideas?

Mark Overton

Ryuji
12-11-2011, 03:11 AM
Mark,

I can no longer point to my website but be very careful about pH meter. Cheap pH testers are not good enough for photographic processing chemicals. Processing chemicals will damage the electrode easily, as they are using silver electrode inside. You need refillable double junction electrode for the reference potential. A classic reference electrode for photographic work was calomel, which is still one of the best choice, but it's just too much mercury to have around. Most cheap electrodes are gel-filled single junction. Don't waste your time or money with those.

One concentrate with powder is not a bad idea. Such a formulation would not be desirable if you were making products but acceptable for private darkrooms.

Ammonium chloride would actually make the image grainier than having nothing at all. It'll give opposite effects to sulfite. You can't just round them all up with a categorical label "silver halide solvent."

Alan Johnson
12-11-2011, 06:43 AM
Yes, good to read your posts again Ryuji.
I wonder if the improved fine grain developer you made might be considered in any respects better than Xtol.

Ian Grant
12-11-2011, 08:22 AM
Kodak supplied the developing agent paraminophenol as the oxalate salt under the tradename kodelon. Therefore their developers would naturally use this salt rather than the hydrochloride. We should not jump to the conclusion that there is any other reason for DK-93 containing a small amount of oxalate.

Oxalic acid is a poorer chelating agent than salicylic acid. In addition we do not know whether it will inhibit oxidation or enhance it.


p-Aminophenol Hydrochloride was also sold by Eastman Kodak as Kodelon and depending on when/where a formula was published may well say p-Aminophenol Hydrochlride or Kodelon.

Mees had worked on p-Amininophenol developers while at Wratten & Wainwright and much of Kodak's work on them was carried out at Kodak Ltd's Harrow Research facility. Kodak UK marketed Kodinol which like M&B Azol, Ilford Certinal etc was a direct competitor for Agfa's Rodinal.

So we need to be careful assuming the possible role of Oxalate in a developer like DK-93 which Kodak published as using Kodelon and elsewhere p-Aminophenol Hydrochloride.

Ian