Improved version of DS-10 by Ryuji Suzuki?

[Rudeofus]

What about EDTA? It's acidic and used in color chems to remove iron introduced by impure Na2SO3.

 

[Ryuji]

I've discussed EDTA, NTA and DTPA many times in the past. There are reasons why I don't use them.

 

[Photo Engineer]

In B&W developers, the Dequest series of chelating agents are better wrt Iron.

PE

 

[Rudeofus]

PE, Mark was looking for acids which don't interfere with the other parts of his developer other than lowering pH. The dequest products you suggested seem to be alkaline to my highly untrained eye. The combination of phosphonates you suggested and one of the acids Ryuji suggested might do the trick, though, lowering the pH and taking care of iron.

 

[Photo Engineer]

I have used Dequests that were in the free acid form and had very low pH. I could therefore adjust the pH to any value I wished.

PE

 

[Rudeofus]

Are these Dequests substances a normal person outside a lab would have access to? As far as I have understood this, Mark is no chemist, neither am I, and neither one of us has access to "special stuff". I didn't even get (NH4)2 FeIII EDTA here . Marks and my approach to mixing devs seems very different from yours and Ryujis ....

 

[Photo Engineer]

Use either 2001 or 2010, and AFAIK they can be purchased. Some companies such as the Formulary will special order for you.

PE

 

[Ryuji]

Speaking of approach, here's my general suggestion:

1. identify what is important (not just useful)
2. determine if it's worth tackling
3. define your goal based on 1 and 2
4. identify challenges (loosely separate from trivial things that require little work to achieve)
5. do research, consult literature and experts, anything it takes to gather relevant information/data to deal with #4
6. consider all possible alternate options and narrow down to the best
7. test, test, test
8. scrap it and start over, unless the result is up to expectation of #3.

Do not add things without knowing what the objective is.
Do not change things without knowing what the objective is.
Do not use things without confirming they are effective and robust.

If you don’t identify a problem, you will not solve anything.
If you don’t define an objective, you will not achieve anything.
If you don’t identify what’s important, your work won’t be important.
If you don’t determine what’s worthwhile, your work won’t be worth much.

Creativity plays role in steps 1 through 6. You have to be critical of your work in steps 7 and 8. Otherwise, you are only fooling yourself.

 

[albada]

Use either 2001 or 2010, and AFAIK they can be purchased. Some companies such as the Formulary will special order for you.
PE

Checking dequest.com, there is no 2001. Did you mean 2000?
Anyway, it's handy that these are available as organic acids. Do you suppose they'll dissolve in PG and/or TEA?
And I see a couple of other Dequest products that don't say they're acidic, such as the 2040 series. Do you recommend those?


An interesting observation:

Only a small amount of ascorbic acid dissolves into 40C PG with much stirring, even after hours of sitting.
But if I add enough sodium metaborate to convert all that AA into sodium ascorbate, it all dissolves in about 1/2 hour with constant stirring.
I attribute this to a difference in solubility limits in PG. I was dissolving 3.6g of AA into 16 ml of PG, and it failed until the metaborate was added.
But this could make TEA problematic because it contains no sodium, and therefore can't create sodium ascorbate. I'll just have to try it...

Mark Overton

 

[albada]

Thanks, Mark, for your great efforts! Based on your thread here I have just ordered a bunch of raw chems and will be ready to try out some stuff in the near future.

Wow! Nice to know that I'm not the only one learning. I find all this very interesting. Once you get your chems, you might try this concentrate:

Propylene glycol .............. 19 ml
Sodium metaborate .......... 2.5 g (2.05g needed to convert ascorbic, giving pH=8.0. rest boosts pH to 8.1)
Ascorbic acid .................. 5.5 g
Phenidone ...................... 0.08 g (adjusted to give 1.5x dev-time)
Propylene glycol to .......... 25 ml (should need to add only 1 ml)

Target pH is 8.1. Dilute 1+39 (i.e., 25 ml makes a liter). Add 60 g/L sodium sulfite to water separately first, and then add the concentrate. Add 50% to XTOL's times.

​

My goal with this test-concentrate was to get XTOL's quality, but using 2/3's of its sulfite and 3/2's of its dev-time, so the sulfite would have about the same solvent-effect. Tests look good, so you might enjoy experimenting with this. I'm tired of pouring so much sulfite into developers, so I decided to try this sulfite-saver idea. You just might be able to dissolve the powders into 15 ml of PG, giving a total of 20 ml and a 1+49 dilution.

Mark Overton

 

[Photo Engineer]

Unless the properties of Dequest have changed, they should sissolve in either PG or TEA depending on polarity.

But, they are not the only sequestrants usable here.

PE

 

[Ryuji]

My goal with this test-concentrate was to get XTOL's quality, but using 2/3's of its sulfite and 3/2's of its dev-time, so the sulfite would have about the same solvent-effect.

If such thing can be done with no negative effects, why do you think Kodak engineers didn’t do it?

 

[Gerald C Koch]

Will do, and thanks for the heads-up.

Another chemistry question: What would be a good acid to mix into TEA to adjust pH and provide decent buffering?

I'm thinking of using only TEA (and no PG) as the carrier for the concentrate, about 22 ml of it per liter of developer. That'll push the pH too high even with the ascorbic acid in it, so another stronger acid is needed to pull it down. I'm hoping that 22 ml of TEA plus an acid to convert some TEA into its conjugate acid (pKa=7.8) will provide sufficient buffering to hold the pH at 8.2 or so. The question is: which acid?

Thanks,

Mark Overton

You can vary the pH of the resulting working solution by using a mixture of TEA and PG for the concentrate. If 't' is the percentage of TEA in the concentrate then (1-t) is the percentage of PG. Using more TEA will results in a higher pH while using less will give a lower pH. Since the developer is a one shot it doesn't need to be buffered. On a thread several years ago I mentioned that I used a mix of equal parts TEA and PG with good results.

 

[Ryuji]

Since the developer is a one shot it doesn't need to be buffered.

Not a good idea. If you have poor buffering system, your operating pH is extremely susceptible to small errors like the amount of ingredients or the pH of the water supplies.

 

[albada]

Unless the properties of Dequest have changed, they should sissolve in either PG or TEA depending on polarity.
But, they are not the only sequestrants usable here.

Good to know, and I've entered this into my chem-notes. Thanks.

If such thing can be done with no negative effects, why do you think Kodak engineers didn’t do it?

Because the 50% boost in dev-time was too negative of an effect?
I also have an untested version of this formula that uses half the sulfite and doubles the dev-time, but that means 7 min for Tri-X becomes 14 min, which will test folk's patience.

You can vary the pH of the resulting working solution by using a mixture of TEA and PG for the concentrate. If 't' is the percentage of TEA in the concentrate then (1-t) is the percentage of PG. Using more TEA will results in a higher pH while using less will give a lower pH. Since the developer is a one shot it doesn't need to be buffered. On a thread several years ago I mentioned that I used a mix of equal parts TEA and PG with good results.

I few postings ago (here: (there was a url link here which no longer exists)), I tried using 5 g/L TEA as the alkali, and got very thin neg's with normal dev-times. The explanation of this failure was poor buffering. That experience made me a buffering fanatic. Well, I was thinking that the best chance at adequate buffering was to use as much TEA as possible, and counter the excess pH with some acid, such as Dequest that PE recommends. And maximum TEA means using it as the sole carrier in a concentrate, as PC-TEA does, which got me going along that line of thinking, which may lead nowhere. Anyway, can you post that equal-part formula? I'd be interested in seeing a successful formula.

Mark Overton

 

[Rudeofus]

If such thing can be done with no negative effects, why do you think Kodak engineers didn’t do it?

Ryuji & PE: Again, you play in a different league. Kodak engineers had to make all the films out there work, had to care about reasonable dev times, people abusing the dev and then bitching about poor results, people finding tiny deviations with expensive densitometers, shipping and storage, cost of raw materials and other things that neither Mark nor I care about.

While I don't follow the Lomo approach in my photography, I will try to pursue a similar approach when it comes to mixing chems. You never know, I may turn into some sort of photo chemist in ten years and if not I at least had fun trying. I will stay away from chems which are Dead Link Removed (I won't get those legally anyway) and those which have to be special ordered from overseas in large minimum order quantities.

My personal goal is to learn lots about this topic and to eventually create developers which can't be just bought:

• devs which create more speed and pushability than Microphen, even if this means large grain or poor acutance. I use a 6x7 format camera and enlarge Delta 3200 to 10x15, 13x18 and 18x24, what do I care about grain? Sure, using 135 format with its faster lenses would gain me 2 stops, but I really like the 6x7 view finder for night shots.
• devs which let me fine tune the balance between grain and acutance in a wide range by adjusting the ratio of a few ingredients, optionally by adding varying amounts of chems to HC-110, my goto developer.
• bend the characteristic curve so it better accommodates shots into direct sun.
• ...

 

[Ryuji]

Kodak engineers had to make all the films out there work, had to care about reasonable dev times, people abusing the dev and then bitching about poor results, people finding tiny deviations with expensive densitometers, shipping and storage, cost of raw materials and other things that neither Mark nor I care about.

One thing you don’t seem to understand is that, XTOL was a disaster in terms of unexpected problems reported by users. There are countless reports of unexplainable sudden failures, where one batch of XTOL working solution works perfectly on the first roll and completely fails on the second roll, processed within an hour of the first roll. I don’t think Kodak officially acknowledged and adequately investigated that problem, but it happened to many people who are known to be meticulous darkroom workers. So, this is one of the topic of my interest and I spent a LOT of effort analyzing it.

HOWEVER, in terms of image quality, XTOL is a fantastic developer. I could tweak some parameters and make it more suitable for certain specific applications, but XTOL was a great new addition to the range of developers. So, if you are trying to *improve* XTOL or DS-10, which could be viewed as a modified XTOL, you’d have to have a very good reason and thorough understanding of how these developers work, because a lot of work has already been done and of course people deliberately took very systematic approach and made very rational decisions. They did not miss a better solution that others can easily find.

By the time XTOL patent application was filed, there were already dozens of US patents on developers using ascorbates. It was nothing new. There were many academic papers discussing ascorbates as developing agents in 1960s, some by Pontinus of Kodak. There was already a wealth of knowledge in this area, and ascorbate was used as a developing agent at laboratory level. There were two ways where XTOL patent was unique in my view. One was to use ascorbate for pictorial quality low contrast fine grain developer (rather than high contrast graphic art film developers, or medical imaging developers, both of which were of significant commercial interest in 1970s and 80s... pictorial b&w developer was almost dead end by then.). Another was to propose a product and packaging rather than the formulation itself. Kodak launched concentrated liquid developers (HC-110, T-MAX and T-MAX RS) but this one came out as two parts powders, and there was a very good reason for it... it could not be prepared as liquid concentrate without losing the quality.

There are some weakness in XTOL, some I mentioned above, and some I discussed several years ago. But overall, XTOL is a very good developer in terms of image quality, and if you try to beat XTOL without thorough understanding of the prior art, as well as a very well reasoned objective, it will fail. If you want to do something anyway, you should start with serious study of XTOL, chemistry and electrochemistry of ascorbates, and the properties of ascorbate developers.

Now, I find some flaw in some of the earlier posts here. Doubling sulfite concentration does not double solvent effect. Well, first of all, how do you define “solvent effect” quantitatively? (There’s actually an answer to this, and it is published and is well known.)

The “solvent effect” does not have equal contribution to the development mechanism or the resulting image quality throughout the development time. So, doubling the development time does not double “solvent effect.”

Then tabular grains have a lot lower rate of dissolution than conventional grains even in the presence of sulfite, so the effect of “solvent effect” is highly dependent on the film.

But then, more solvent effect does not mean finer grain. HC-110 has powerful silver halide solvent but the image is very grainy. So, optimal fine grain does not coincide with maximal solvent effect.

Now, wouldn’t it make sense at least to study and try to understand why XTOL contains that much sulfite? Don’t you think that will give you a strong hint of what can be done and what will be wasted effort?


Well, one might ask: what is the minimum quantity of sulfite in XTOL type developers wherein development at stock strength produces comparable (although may not be exactly the same) granularity and sensitometric properties?

That same question was studied for Eastman MQ borax fine grain developer (a.k.a. D-76) from late 1920s to 1940s, and the answer is published and well known. The question is whether the same number works for XTOL with modern film. That answer, as far as I know, is not published so I tested it myself. Why do the answer might differ?

 

[Alan Johnson]

Wow! Nice to know that I'm not the only one learning. I find all this very interesting. Once you get your chems, you might try this concentrate:

Propylene glycol .............. 19 ml
Sodium metaborate .......... 2.5 g (2.05g needed to convert ascorbic, giving pH=8.0. rest boosts pH to 8.1)
Ascorbic acid .................. 5.5 g
Phenidone ...................... 0.08 g (adjusted to give 1.5x dev-time)
Propylene glycol to .......... 25 ml (should need to add only 1 ml)

Target pH is 8.1. Dilute 1+39 (i.e., 25 ml makes a liter). Add 60 g/L sodium sulfite to water separately first, and then add the concentrate. Add 50% to XTOL's times.

​

My goal with this test-concentrate was to get XTOL's quality, but using 2/3's of its sulfite and 3/2's of its dev-time, so the sulfite would have about the same solvent-effect. Tests look good, so you might enjoy experimenting with this. I'm tired of pouring so much sulfite into developers, so I decided to try this sulfite-saver idea. You just might be able to dissolve the powders into 15 ml of PG, giving a total of 20 ml and a 1+49 dilution.

Mark Overton

Is there is a mistake here?When the 60g/L sodium sulfite is added the pH will rise to about 9.5.The earlier idea of keeping the pH~8 was more promising.Will the concentrate addition get it to this level?

Still ,it may be possible to get a better result from a concentrate than I got from PC-TEA, linked in my last post.A concentrate as fine grain as Xtol is not a viable aim but you may be able to make a better concentrate than PC-TEA for fine grain.It's easier to test with 400 ISO traditional film which has larger grain.
I just said solvent action as shorthand.Here is a more detailed description under development technique:
http://www.imx.nl/photo/Film/Film/Film/page39.html

 

[Gerald C Koch]

Not a good idea. If you have poor buffering system, your operating pH is extremely susceptible to small errors like the amount of ingredients or the pH of the water supplies.

There are examples of poorly buffered developer concentrates. For example, the catechol-caustic formulae that were once popular. D-23 and that old standby D-76 are poorly buffered.

 

[Rudeofus]

HOWEVER, in terms of image quality, XTOL is a fantastic developer. I could tweak some parameters and make it more suitable for certain specific applications, but XTOL was a great new addition to the range of developers. So, if you are trying to *improve* XTOL or DS-10, which could be viewed as a modified XTOL, you’d have to have a very good reason and thorough understanding of how these developers work, because a lot of work has already been done and of course people deliberately took very systematic approach and made very rational decisions. They did not miss a better solution that others can easily find.

As I mentioned before, I don't think little Rudeofus with his admittedly highly limited knowledge of chemistry overall and photochemistry in particular will revolutionize film developers. I don't think Mark attempts that either. In spite of the huge challenge we face here there are, however, a few things that work in our way:

• We don't have to beat XTOL. 99.99% of all users may judge Rudeofus-01 as complete disaster because it lasts 1 hour, develops few films except Delta 3200 and Tri-X and produces golf ball sized grain. But if I get it to do some special things with Delta 3200 that I like, I am happy. Neither Mark nor I will be able to sell our compositions, and we can call ourselves happy if anyone even bothers looking at our recipe. Both Mark and I are free of market pressure.
• I see learning as a positive thing in itself and I am highly grateful that PE and you offer your vast knowledge on this subject. Please be patient with us fools in a time where few even care about b&w chemistry and where chemistry kits are sold with "60 fun experiments without chemicals". If all my experiments produce nothing but 20 expensive rolls of comprehensive failure, I've learned more about photo chemistry than all the folks who just rant "Ryuji, when are you going to send me your next powder developer", and I may end up with more appreciation for your work, skill and knowledge than folks who just scream for finer grain and ISO 25600.
• A lot of the published recipes were formulated at a time when epitaxial or T grain did not exist. Mark and I at least know which films our soup has to work with now. As has been mentioned here and elsewhere, a lot of "old" knowledge doesn't work with Delta or TMAX.
• XTOL can go away if some bean counters at Kodak decide they don't like it no more. These 50g of Phenidone that I will pick up this evening will stay in my stash for a long time.

There are some weakness in XTOL, some I mentioned above, and some I discussed several years ago. But overall, XTOL is a very good developer in terms of image quality, and if you try to beat XTOL without thorough understanding of the prior art, as well as a very well reasoned objective, it will fail. If you want to do something anyway, you should start with serious study of XTOL, chemistry and electrochemistry of ascorbates, and the properties of ascorbate developers.

Serious study of other developers and the associated chemistry is imperative, I agree, and will happen automatically once we proceed and run into our first obstacles. Yet we like to play with our toys even if we don't fully understand how they work. It's a hobby for Mark and myself so we are entitled to having fun pursuing it

Now, wouldn’t it make sense at least to study and try to understand why XTOL contains that much sulfite? Don’t you think that will give you a strong hint of what can be done and what will be wasted effort?

As mentioned before, fine grain is an afterthought for me as there are lots and lots of ultra fine grain developers readily available, so why would I mix them myself (except for educational purposes)? I don't want to mix stuff that everybody wants, I want to be able to mix stuff which few people or only I want and which is therefore not commercially available.

 

[Gerald C Koch]

Mark,

It's been a long time and I can't find my recipe but here goes

Propylene glycol 50 ml
Ascorbic acid 10 g
Dimezone 0.28 g ???

Heat gently until the developing agents dissolve and allow to cool and then add

TEA 50 ml

I am not sure about the amount of Dimezone.

Jerry

 

[albada]

Is there is a mistake here?When the 60g/L sodium sulfite is added the pH will rise to about 9.5.The earlier idea of keeping the pH~8 was more promising.Will the concentrate addition get it to this level?

Sorry, I didn't communicate clearly. The pH will be 8.1 after adding the sulfite and concentrate together. You're right; it'll be different before adding sulfite. BTW, I suggest adding sulfite first (and then concentrate) to scavenge oxygen. My preliminary tests show that this developer produces quality similar to XTOL, so I think Rudeofus would enjoy trying it out. I've only made a few test-strips with TMY-2, so there has not been enough testing done for me to recommend this developer to people in general.

Ryuji says that solvent-effect is not proportional to dev-time, but I'll at least try a new concentrate that cuts the (separately added) sulfite in half and doubles dev-time and see what it looks like. It seems that when I try something, I often get a "surprise". :confused:

Ryuji: A few posts ago, you said that using TEA as the sole carrier in a concentrate is a poor idea. Yet PC-TEA uses this approach. What specific problems occur with doing that? If it's not feasible for a specific reason I'm interested in, then I'll drop that pursuit.

Mark Overton

 

[albada]

Propylene glycol 50 ml
Ascorbic acid 10 g
Dimezone 0.28 g ???

Heat gently until the developing agents dissolve and allow to cool and then add
TEA 50 ml
I am not sure about the amount of Dimezone.

Thanks for the formula. I seem to recall reading this somewhere, but my searches don't find it.
Dimezone is in the latest batch of chems that arrived a couple of days ago, so it's time to use that instead of phenidone.

Mark Overton

 

[Photo Engineer]

Mark, Rudeofus;

You have both hit on some topics that are familiar to me. A developer from Kodak must be capable of working well with a wide variety of films. We tested loads of films and I still have some of the Fuji and Agfa C41 cross comparisons from tests I ran years ago.

Long development times gave good results but they worried about customers reactions. This is a good point. But, long development times gave good results!

Low buffer capacity made the developer more variable but gave better edge effects due to the micro drop in pH in some image areas with some films. But this did not work for all films.

Therefore, Kodak developers were broad spectrum formulas, but you may be able to optimize a formula for one film or one family of films that is superb.

Don't be discouraged.

PE

 

[Keith Tapscott.]

Using D-76, ID-11 or Xtol diluted 1+1 or full-strength and replenished is much less hassle than trying to formulate something that's so complicated but only offers a very modest difference in image quality.