Improved version of DS-10 by Ryuji Suzuki?

[Ryuji]

Guys, sorry I had to take the silvergrain labs site down. The software platform was complicated and too costly to maintain, plus I make living shooting photography not maintaining websites or sharing information. If there's demand maybe I could make an e-book or something... but seriously I need interns to do that.

Regarding DS-12, this formula has not been in use for some time. However, I've devised a formula that perhaps could be described as roughly halfway between DS-10 and 12, or perhaps better way to say it might be an ascorbate version of Microphen/DD-X. This film developer gives grainless and sharp image with 35mm TMX or Acros in 20x24 enlargement (and gives at least box speed at normal contrast). This was once prepared as liquid concentrate. I actually had many bottles of this developer, manufactured and packaged in my previous lab space in Downtown Boston, and ready to ship out as commercial samples... but now I'm reformulating it in all powder form. I'm actually eager to test it with 400TMY-2. I actually never shot 400TMY-2, but that seems to be one obvious thing to try, since what I want to do with film now requires best IQ and speed.

But please be patient. I'm not interested in spending all day discussing trivial matters on chemistry. I'm interested in creating images and furnishing myself with necessary technology. When this developer in question is prepared, tested in my new studio, you'll hear from me somehow.

 

[albada]

At PE's suggestion, I scanned the test-strips for XTOL (6.5 min at 20C for TMY), and for the concentrate shown below, which was posted earlier in this thread (there was a url link here which no longer exists):

Propylene glycol ................. 39 ml
Ascorbic acid ..................... 10.7 g
Sodium metaborate ............. 6.5 g
Phenidone .......................... 0.15
Propylene glycol to ............. 50 ml (you should only need to add about 1 ml)
​

This should be diluted 1+19, making 1 liter of working solution. My dev-time was 7.5 min at 20C for TMY.

Here is the XTOL scan:
And a crop:

And here is the scan of the above formula:
And a crop:

These images are darkish because I set the white-point as high as possible in the scanner, to clip as little data to white as possible (i.e., maximize the dynamic range). The black-point was set to the left side of the histogram (which was always the same). Gamma was 1.5.
This is part of my camera-collection, lit by the overhead tungsten candelabra. It's hard lighting, which creates plenty of specular reflections to see how the dense part of negatives are doing. Unfortunately, my Coolscan IV ED scanner doesn't have enough dynamic range to cover such specular reflections well (and still show shadow-detail in the neg's), so many reflections clip to white.

In the crops above, my formula appears to have less grain than XTOL. That's not true. In 22X loupes, they seem to have the same grain. The scanner's focus has a little variation, and the film isn't held perfectly flat, so grain is defocussed by unpredictable amounts. To get sharp images of grain, I want to photograph negatives in a microscope.

Mark Overton

 

[Photo Engineer]

Thanks Mark;

IMHO the experimental developer looks less sharp. Look at the numbers on the lens in both crops. The grain is similar and low.

PE

 

[albada]

Thanks Mark;
IMHO the experimental developer looks less sharp. Look at the numbers on the lens in both crops. The grain is similar and low.
PE

Oops, that was poor scanner-focus, being near the edge of the neg-carrier.
I re-scanned that neg, but this time manually focusing the scanner on that crop-area. That made the scan sharper there:



Mark Overton

 

[Photo Engineer]

Thanks again. Looks better now. There is some "hash" on the right top in the dense areas.

Both developers look similar in contrast to me when viewed as thumbnails. I can't view them side-by-side for a more accurate examination. Just keep on working. looks interesting and you are learning as you go.

PE

 

[albada]

Here's a failure I'd like some advice about.

Moving toward creating a concentrate, I modified the PC-Sulfite formula by replacing the sodium sulfite with TEA. The big difference between this and PC-TEA is the pH is much lower, and thus there's more AA and phenidone per liter to keep the dev-time at 7-8 minutes. Here's the 1-liter test-formula:

TEA ................. 5 ml
Ascorbic acid ... 2.7 g
Phenidone ....... 0.18 g
pH = 8.3

​

The AA and phenidone are about the same as PC-Sulfite, and the pH is the same. So I expected the dev-times to be the same. But 7.5 min at 20C produced a very thin test-strip. A second strip at 9.5 minutes was also thin, plus the developer had turned light yellow. Adding a little more ascorbic acid made it clear again.

I even tried quadrupling the TEA and AA (keeping the pH at 8.3), and an 8 minute time gave negatives that were a little thin, and yellowish developer again. It seems that the developer is quickly becoming exhausted or oxidized.

Any idea why?

I know that sulfite is an antioxidant, but ascorbic acid is an even stronger antioxidant, so I'm surprised that swapping out the sulfite caused this.
Further mysterious is the fact that PC-TEA does not exhibit this problem, and it has even less AA and phenidone per liter than my formula above. However, PC-TEA operates at a high pH around 10, and I'll speculate that that high pH is activating the phenidone in PC-TEA rather than the AA. But that's just my speculation...

Mark Overton

 

[Photo Engineer]

Mark;

Perhaps you have missed the buffer capacity of the Sulfite compared to TEA among other things, and that involves the molecular weights as well. Look at the moles per liter of TEA and Na2SO3.

PE

 

[albada]

Perhaps you have missed the buffer capacity of the Sulfite compared to TEA among other things, and that involves the molecular weights as well. Look at the moles per liter of TEA and Na2SO3.

I forgot to mention: The pH was the same after development as it was before (8.3). I checked this on the second run wondering the if pH had plunged. I even checked pH once a minute while developing a leader -- always at 8.3. So I don't think poor buffering is the culprit.

Sulfite and TEA have similar molecular weights: 126 vs 149. So even after quadrupling, I was putting far fewer moles/liter in there. But given that pH is constant, I don't know what harm fewer moles of alkali would do.

Mark Overton

 

[Photo Engineer]

Mark;

The pH does not give one the buffer capacity. They are not the same. One refers to the inertia of the movement of the pH with any addition of acid and the other refers to just an absolute number of Hydrogen or Hydroxyl ions present. So, Na2SO3, if it ionizes more fully than TEA even at the same weight, will probably buffer better. That is poorly stated but gives a gist of the situation.

Since SO3-- puts more Ag+ into solution being a mild solvent, a mix of DEA/MEA/TEA might simulate SO3--. IDK. Try it. I have my own solutions to this problem.

PE

 

[Alan Johnson]

Here's a failure I'd like some advice about.

Moving toward creating a concentrate, I modified the PC-Sulfite formula by replacing the sodium sulfite with TEA. The big difference between this and PC-TEA is the pH is much lower, and thus there's more AA and phenidone per liter to keep the dev-time at 7-8 minutes. Here's the 1-liter test-formula:

TEA ................. 5 ml
Ascorbic acid ... 2.7 g
Phenidone ....... 0.18 g
pH = 8.3

​

The AA and phenidone are about the same as PC-Sulfite, and the pH is the same. So I expected the dev-times to be the same. But 7.5 min at 20C produced a very thin test-strip. A second strip at 9.5 minutes was also thin, plus the developer had turned light yellow. Adding a little more ascorbic acid made it clear again.


Mark Overton

I made up this solution in tap water and measured its pH.
I get pH= 8.0 with an inexpensive pen type meter,but it calibrates accurately vs 2 buffers.
btw there are 2 types of TEA, 97% and 99% and they have different pH. I used 97%.
So partly pH may be a factor in your result. Also, not mentioned, sulfite is known to dissolve some silver halide and uncover latent image centers which TEA may not do and this may be a factor as well.

 

[albada]

I get pH= 8.0

This pH-difference might be due to measurement-variations. I mix 200 ml test-solutions, and divide the formula by 5. For this, that means 1 ml of TEA and about 1/2 gram of AA. The 1 ml of TEA makes the pH swing a long distance, from 3.0 to 8.3. That's a range of 8.3-3 = 5.3. A shift of 0.3 represents a 6% shift over that range. For small liquid quantities, I use a syringe with a 3 ml capacity, and which is graduated in 0.1 ml increments. I can probably get within 0.05 ml with it. That's a 5% random variation in my measurement right there. So your 8.0 versus my 8.3 is probably due to measurement-variation.

Did you try a clip test with this formula? Even 10 minutes at 21C gave me a thin clip.

Mark Overton

 

[Rudeofus]

Mark,

could you find out whether that clip ever turns normal if you dev long enough? PE suggested in some previous post that at EK they investigated slow developer for extra fine grain. Since your pH seems to linger around the lowest possible value for B&W dev (according to what Ryuji posted), you may have inadvertently walked the path Ron suggested.

About your pH measurements: nobody expects your whole liquid to change pH from the couple of silver grains reacting with your dev, but locally the pH could change thereby reducing contrast (similar to stand development). The easiest way for you to find out is by changing agitation: if strong agitation creates much thicker negs, some local effect may be the culprit and buffering could help.

If your test clip turns normal after much longer dev, it would be interesting to see results, especially with regard to grain. On the one side you achieved extra slow development, on the other side you omitted Na2SO3 which acts as a grain solvent.

 

[Photo Engineer]

Rudeofus:

I had wondered that same thing, but didn't bring it up. His developer is nothing like ours so I didn't think of it in this context. So yes, he may have gone down the same path but with a different formula. Very good idea to try a very long development time and see what happens.

PE

 

[Alan Johnson]

Mark,
I developed APX100 24min 20C and got good negs in your last posted brew.Maybe a bit overdeveloped.
Gainer found that to get max contrast for a given development time you need 40:1 ascorbate/phenidone ratio.
http://unblinkingeye.com/Articles/Synergism/synergism.html
Xtol has about this ratio.
With no buffer to get pH~8 you have 2.7:0.18 only 15:1.
So you have to develop a lot longer than Xtol to get the contrast.

 

[albada]

Mark,
I developed APX100 24min 20C and got good negs in your last posted brew. (snip) With no buffer to get pH~8 you have 2.7:0.18 only 15:1.
So you have to develop a lot longer than Xtol to get the contrast.

How does the grain look compared to other developers you've used? Hmm, at 100 speed, maybe you'll need a 100x microscope to tell. Also, did the developer turn yellow? And what agitation-method do you use? I agitate for 6 sec, once per minute.

Regarding 15:1: The paradox is that this formula is the nearly the same as PC-Sulfite, except for a different alkali. And PC-Sulfite only needs around 7.5 minutes, operating at the same pH. I've been thinking that dissolved oxygen was destroying ascorbate, but maybe not.

could you find out whether that clip ever turns normal if you dev long enough? (snip) If your test clip turns normal after much longer dev, it would be interesting to see results, especially with regard to grain. On the one side you achieved extra slow development, on the other side you omitted Na2SO3 which acts as a grain solvent.

I'll re-mix and try that, but it looks like Alan beat me to it. Anyway, I'll try both normal and continuous agitation.
The possibility of micro-crippling due to poor buffering also occurred to me while driving to work this morning. I got some thin-but-probably-usable negs, and I'll re-examine them for shadow-detail.

TEA has some solvent ability, so 20+ minutes in it might do nice things for the grain. Although at only 5 ml/L, I'm not holding my breath.

For those who want to experiment with this, you can multiply the amount of TEA and AA by the same factor, and the pH will change only slightly. That might be a way to get enough TEA in there to improve buffering and get some solvency-effect. Also, the AA/phenidone ratio will rise by that factor, which will also increase activity somewhat proportionately until levelling off after the ratio goes above 40.

Mark Overton

 

[Alan Johnson]

You might keep an eye open for an increase in shadow speed.
Sometimes when a developer takes a long time to reach normal contrast this gives the shadows extra time to develop.Maybe not with sulfite as some of the latent image specks are dissolved, but TEA may do this.

 

[albada]

Following Alan's example, I developed the new strip for 20 minutes at 20.5C. The results compared to XTOL:

• Slightly higher overall density.
• Higher fog.
• Grain is significantly coarser.
• Slightly less shadow-detail (i.e., loss of speed).

It seems to me that this developer needs a halide-solvent to improve grain and speed.

Mark Overton

 

[albada]

Well, try using Potassium Sulfite.

Regarding solvent-power, how much Potassium Sulfite should I use? The molar-equivalent of Sodium Sulfite?

I ordered some 48% concentrate today, along with Dimezone-S.

Mark Overton

 

[Alan Johnson]

It seems to me that this developer needs a halide-solvent to improve grain and speed.

Mark Overton

If you want a glycol only developer with no sulfite,it has been done. But it looks like quite a research project to me.
http://photo.net/minox-camera-forum/00VpUe
That has a lot of phenidone and little ascorbate as it is for microfilm.
1,2-propanediol is propylene glycol.
Notably is appears to use thiocyanate as silver halide solvent.
There are hazards with this but thiocyanate is used in toner.

 

[Photo Engineer]

Mark;

Start with the molar equivalent.

PE

 

[Rudeofus]

And make sure you properly account for bound water molecules when comparing sodium and potassium sulfite. IIRC both come with varying amounts of water per molar unit, make sure you know which one you have in front of you.

 

[albada]

And make sure you properly account for bound water molecules when comparing sodium and potassium sulfite. IIRC both come with varying amounts of water per molar unit, make sure you know which one you have in front of you.

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

 

[Rudeofus]

Here's a list of acids or acidic substances I have found in b&w developers which I think do not act as development or chelating agent: boric acid, sodium metabisulfite, salicylic acid.
Salicylic acid is soluble in organic solvents so this could be perfect for your recipe. Ryuji uses it in his DS-12 formulation!

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. Right now I'm a little bit worried about heating TEA in my flat with two small children around (they have sustained 4 years of E6/C41 so far ) but I have access to a dark room once a week so we'll see how far I get.

 

[Alan Johnson]

Mark,
Xtol contains~0.2g/L dimezone S (phenidone derivative),sulfite @ 85 g/L is a good solvent.
PC-TEA 1:100 contains 0.025g/L phenidone, sulfite @50g/L was not a good solvent in my test at pH ~8:
(there was a url link here which no longer exists)
If my result was right, the sovent effect depends on the concentration of phenidone-ascorbate in the working solution as well as the sulfite.
It looks like your concentrate, when decided upon, after dilution will give a phenidone concentration beween the two quoted above.
I hope you get a good solvent effect if a fine grain is the wanted result.

 

[Ryuji]

Here's a list of acids or acidic substances I have found in b&w developers which I think do not act as development or chelating agent: boric acid, sodium metabisulfite, salicylic acid.
Salicylic acid is soluble in organic solvents so this could be perfect for your recipe. Ryuji uses it in his DS-12 formulation!

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. Right now I'm a little bit worried about heating TEA in my flat with two small children around (they have sustained 4 years of E6/C41 so far ) but I have access to a dark room once a week so we'll see how far I get.

There are lots of acids that can be used. Malic acid, citric acid, gluconic acid, phosphoric acid, sulfamic acid, sulfuric acid, etc. However, the idea of using triethanolamine as the carrier solvent is probably unwise for practical reasons.

Also, many of the acids above have interaction with iron, potentially useful but potentially harmful. Also, technical grade of those acids may contain a significant amount of iron as impurities. I'd be careful in choosing ingredients.

If anyone wants salicylic acid, I have a LOT of them and don't plan to use much more of them, so I'd be happy to unload some. Email me directly.