Improved version of DS-10 by Ryuji Suzuki?

[Photo Engineer]

Lowering of pH due to lack of buffer capacity can lower contrast overall, lower Dmax, or increase edge effects in borders between objects of different density.

It depends on film and developer composition.

PE

 

[Photo Engineer]

Sulfite at this level tends to act as a mile silver halide solvent much as it does in D-76. As we all know, it is also a stabilizer (antioxidant) and a mild alkali or a weak base.

PE

 

[Photo Engineer]

It looks like D-76 with the HQ and Metol replaced by the Phenidone and AA. IDK. There is no great synergy between P and AA but there is between Metol and HQ which is what makes it work. Try it. I suspect again it will depend on film and will need some tinkering. These things always do.

We went through many variants for TF-5 and Liquidol to come up with final formulas that performed as they now do.

PE

 

[BradS]

I remember reading a posting somewhere that tests showed that having too much ascorbate (ascorbic acid?) in a developer is harmless. If so, we can add extra to drop the pH to 8.0. That means we can also delete the boric acid, resulting in this simple formula:

Water ................................... 750 ml
Phenidone ............................ 0.15 g developer
Ascorbic Acid ....................... 14.3 g developer, and adjust pH to 8.00
Sodium Sulfite (anhydrous) .... 75 g alkali and halide-solvent
Water to make ...................... 1 L
​

Mark Overton

Is the ascorbic acid going to act as a developing agent at this pH ? I don't think so.

 

[BradS]

You must remember that there are trade off situations. The developers at Kodak cost millions of dollars to develop. All others were done on a shoestring by comparison.
(...snip...)
PE

I think this is why I keep coming back to plain vanilla D-76. There is a reason that it has been around so long and ther eis a reason that virtually every commercially viable producer of developers fro B&W films has offered an "equivalent" to D-76. Similar ideas apply to XTOL (and maybe even Dektol?).

 

[Photo Engineer]

There are several variations on Dektol that offer different degrees of similarity and improvement. Same thing as with D76.

PE

 

[albada]

But if the pH, and therefore activity is low enough the film spends a significantly longer amount of time in contact with the sulfite. I'm thinking here of how D25 works compared to D23, although they both have more sulfite and don't use phenidone.

Am I wrong in thinking the formula:

Water ................................... 750 ml
Phenidone ............................ 0.15 g developer
Ascorbic Acid ....................... 14.3 g developer, and adjust pH to 8.00
Sodium Sulfite (anhydrous) .... 75 g alkali and halide-solvent
Water to make ...................... 1 L

...would be a very low energy developer? This seems almost like a POTA variant with lower pH.

Keep in mind that this formula is an attempt to simplify Ryuji Suzuki's DS-10, which has the above amounts of phenidone and sulfite. It likewise has a pH of 8.00, but it uses different acids/alkalies to achieve 8.00, whereas I increased the ascorbic acid to do so. So with the same pH and sulfite, and equal or greater quantities of same developers present, I'm hoping this formula will behave like DS-10. Although PE warns me (in different words) that things don't always (even usually?) work as expected.:confused:

I got the order with Photo Formulary straightened out, I'll soon have some ascorbic acid for tinkering with this.

Mark Overton

 

[Gerald C Koch]

Ryuji said in a pure-silver posting, "At this point I do not recommend to store DS-10 for any more than a couple of weeks." Farther down in that posting, Ryuji says, "At this point, I mix DS-10 as I use."

Here's the link: http://www.freelists.org/post/pure-silver/DS10-information,1

So yes, it makes one question the addition of chemicals for preservation.

Mark Overton

I think that Ryuji was being conservative at this point because he hadn't finished testing for the developer's storage life. The Stability Constant for the iron-salicylate complex is 6.55 which I think is adequate.

 

[Gerald C Koch]

Solubility of Salicylic acid in water is given here as ~2g/L
http://en.wikipedia.org/wiki/Salicylic_acid

In DS-10 you are not dealing with pure water but with an alkaline solution which will increase the solubility.

 

[Gerald C Koch]

I like removing ingredients while only half-knowing what I'm doing.
Mark Overton

Saying that a formula has too many ingredients is like saying that Mozart's music has too many notes. In a developer each of the ingredients has a purpose. Remove things at your own peril. You cannot remove the TEA or salicylic acid without changing the developer's pH among with other effects.

 

[nworth]

I wonder what a little bit of EDTA-Na would do for stability.

 

[Photo Engineer]

I would like to see the complexation constants for Ferric EDTA and Ferric Salicylate in the same medium and at the same concentration.

I can't seem to find this information yet.

PE

 

[Gerald C Koch]

I came across a list www.coldcure.com/html/stability_constants.html which contained mostly compounds involved in human physiology like amino acids but which also contained the following

ferric salicylate 16.35 ferrous salicylate 6.55
ferric EDTA 25.7 ferrous EDTA 14.3
ferric NTA 15.87 ferrous NTA 8.84

salicylate constants seems to roughly comparable to those of NTA in stability.

 

[Gerald C Koch]

I wonder what a little bit of EDTA-Na would do for stability.

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.

 

[Photo Engineer]

Then i would suggest NTA as a replacement for Salicylic acid for a trial run.

NTA is used in Bleach iii for C41 IIRC. At least it was undergoing trials when I retired.

Thinking this over for a bit, I have to add that you need more than the constants given above. You need to know the oxidation potential of the Fe III ion when complexed and when not complexed to make a full judgment.

PE

 

[albada]

Success!
The graininess and shadow-detail of the simplified DS-10 matches XTOL.
BTW, this is the first time I've ever formulated my own developer. Nothing like learning something new when you're 54 years old!

However, PE was right. pH was a surprise, and just 9g of ascorbic acid with 75g sulfite (per litre) pushed the pH lower than I thought (to 7.2). Adding a little borax didn't help enough, so I added some sodium carbonate to hit the target pH of 8.0. Here's what I ended up with:

Phenidone ............... 0.15 g
Ascorbic acid .......... 9 g
Sodium sulfite ......... 75 g
Borax ..................... 1.5 g
Sodium carbonate ... 1.5 g
Water to 1 L
Develop for 10 min at 20C/68F.

​

I'd like to reduce the ascorbic acid to 8 g/L (40:1 ratio with phenidone), and replace the alkalis with only borax or preferably TEA ... when it arrives in the mail in 6 days.
It would be better to measure the phenidone more accurately. It's difficult even with an electronic gram scale with 0.01g resolution.

Finally, I hope to dissolve most stuff in propylene glycol (a la PC-Glycol), yielding a developer that gives XTOL-quality at near-HC110 convenience.
This is fun. Where have I been in the last 54 years?

Comments are welcome.

Mark Overton

 

[Alan Johnson]

Here is the formula of Gainer's PC Borax:

Phenidone.....................0.15g
Ascorbic Acid.................6.0g
Borax decahydrate..........19g
Water to.......................1L
pH~9
Develop for D-76 times.1L is said to process 12 rolls film.

I have used this, it works well.
It looks like you are on the way to making a somewhat similar developer but with added sulfite and lower pH to give finer grain.They usually put a little sodium metabisulfite in to make a buffer (Xtol,Mytol).
Hope you reveal your next formula.

 

[Gerald C Koch]

Hi Mark,

There is a principle in chemistry which can be summed up as "Like dissolves like." What this means is that in general organic chemicals dissolve most readily in organic solvents and inorganic ones in an inorganic solvent. The Phenidone and ascorbic acid will dissolve in such solvents such as propylene glycol but everything else in your formula will not. When Kodak decided to develop HC-110 which contains no water, they were forced to use some chemical tricks pH was controlled using a mixture of TEA and DEA. Since they couldn't use potassium bromide they had to use an addition product of hydrogen bromide and an amine. These chemicals are not readily available and certainly not to the home experimenter. Some are also dangerous. If you look at the threads for glycol based developers on APUG you will find that they consist of developing agents and maybe TEA. They cannot contain sulfite or bromide and so have limited flexibility.

Developing a useful developer is a very difficult task and requires a very good foundation in chemistry. The two chemists who developed Xtol worked for a year before they had a tentative formula that they could show to Kodak management. That's a lot of man-hours. For example, are you aware that for any developer with a superadditive combination of developing agents such as Xtol or D-76 that there is an optimal ratio of the two developing agents? You cannot just change the concentration of one agent willy-nilly and expect a good result.

If you wish to continue experimenting then you will need a good book on photochemistry. Grant Haist's two books are the most current but there is also Mason and Glafkides.

Good luck
Jerry

 

[albada]

It looks like you are on the way to making a somewhat similar developer but with added sulfite and lower pH to give finer grain.They usually put a little sodium metabisulfite in to make a buffer (Xtol,Mytol). Hope you reveal your next formula.

Alan, thanks for the formula and the chemistry clues. I need chemistry clues because photochemistry and developer-engineering are new to me, as you'll see in my response to Gerald below. Yes, it looks like I'm heading toward a PC-Borax plus sulfite. I encourage you to try it first. /2

How exactly did OP evaluate the graininess, sharpness, speed and curve shapes for different contrast gradients in comparison to XTOL?

Michael, my tests are so early and preliminary that no sensitometric (sp?) measurements have been done. I simply visually compared scans from a Nikon Coolscan on the monitor, where black-point/white-point/gamma were assigned identically in the scans.

<good information clipped>
If you wish to continue experimenting then you will need a good book on photochemistry. Grant Haist's two books are the most current but there is also Mason and Glafkides.

I have these books: Film Developing Cookbook, Darkroom Cookbook, Photographic Chemistry (Eaton, too shallow), and Photographic Processing Chemistry (Mason). I would love to get a hold of Haist's set, but his books cost a few hundred dollars (I've hunted for them). I suspect they are a better investment than classic cameras. or maybe that should be
Anyway, Mason is by far the most thorough text I have, and I wish I had more information still. At your suggestion, perhaps I'll drop the $$$ into Haist's work. Which volume should I get? Well, I'm gathering many bits and pieces from the Internet. At this point, I only know some simple rules, and not even enough of them, such as the "like dissolves like" which you pointed out. My ignorance of photographic chemistry is frustrating, and I'm learning as fast as I can.

Here's an idea I thought of while in the shower: Go ahead and add insoluble chemicals to propylene glycol or TEA. They won't dissolve, so they'll be in a suspension, and will settle to the bottom of the bottle. Before measuring out some concentrate, shake the bottle to get the insolubles back into suspension. I think this can only work if (1) those solids don't cake (stick) together when settled at the bottom, and (2) the viscosity of the concentrate is reasonably low to allow quick dispersion by shaking. Any thoughts on this? Should this idea go down the shower-drain from whence it came?

Mark Overton

 

[nworth]

I was looking at something else recently, and I was reminded that oxalic acid is another excellent sequestering agent for iron. Oxalates were used in several early developers, but DK-93 is the only one that remains well documented. IIRC, it had pretty good keeping properties, but so does the related Rodinal. Has anyone explored this with ascorbic acid developers?

 

[P C Headland]

Success!
The graininess and shadow-detail of the simplified DS-10 matches XTOL.
BTW, this is the first time I've ever formulated my own developer. Nothing like learning something new when you're 54 years old!

......

I'd like to reduce the ascorbic acid to 8 g/L (40:1 ratio with phenidone), and replace the alkalis with only borax or preferably TEA ... when it arrives in the mail in 6 days.
It would be better to measure the phenidone more accurately. It's difficult even with an electronic gram scale with 0.01g resolution.

Finally, I hope to dissolve most stuff in propylene glycol (a la PC-Glycol), yielding a developer that gives XTOL-quality at near-HC110 convenience.
This is fun. Where have I been in the last 54 years?

Comments are welcome.

Mark Overton

Given you want Xtol quality with near HC110 convenience, you may want to mix up a small batch of PC-TEA. You'll have the ingredients to hand.

My admittedly limited experience led me to thinking of PC-TEA as like a cross between Xtol and Rodinal, taking the best (for me) features of each. My more experienced friend likened it to the best of Xtol and HC110.

Have fun with the experiments.

 

[Gerald C Koch]

I was looking at something else recently, and I was reminded that oxalic acid is another excellent sequestering agent for iron. Oxalates were used in several early developers, but DK-93 is the only one that remains well documented. IIRC, it had pretty good keeping properties, but so does the related Rodinal. Has anyone explored this with ascorbic acid developers?

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.

 

[albada]

Given you want Xtol quality with near HC110 convenience, you may want to mix up a small batch of PC-TEA. You'll have the ingredients to hand.
My admittedly limited experience led me to thinking of PC-TEA as like a cross between Xtol and Rodinal, taking the best (for me) features of each. My more experienced friend likened it to the best of Xtol and HC110.
Have fun with the experiments.

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: (there was a url link here which no longer exists)
So I'm thinking of trying some of that Instant Mytol.

Mark Overton

 

[albada]

Regarding not storing DS-10 for more than two weeks:

I think that Ryuji was being conservative at this point because he hadn't finished testing for the developer's storage life. The Stability Constant for the iron-salicylate complex is 6.55 which I think is adequate.

I found a quote by Ryuji where he says that "DS-10 is a very good fine grain film developer, but it should not be kept for more than a couple of weeks, as I've seen cases where developer went off after that period." Here's the link: (there was a url link here which no longer exists)

He doesn't say under what conditions it went off. Perhaps it would last longer if kept cool and air in bottles displaced with inert gas. Gerald reports having no problems after a month.

Mark Overton

 

[P C Headland]

The good thing about PC-TEA is that it seems to have keeping qualities more akin to Rodinal / HC110 than Xtol. Like Rodinal, it darkens once opened, but it's activity seems to stay the same. I'm still working my way through a batch I made almost 5 years ago.