A very low contrast, low pH, full speed POTA variant

Alan Johnson · Jan 28, 2014

In the previous work, Crawley used 0.25g/L phenidone and no metol in FX-3, 0.5g/L phenidone and 1.5g/L metol in FX-4.The speed increase with FX-4 was about 30%.
But he was not looking to make a low contrast developer .The oxidation product of phenidone I believe gives the low contrast.

removed account8 · Jan 28, 2014

Xmas: I'm not looking for buffering. In fact I'd like to avoid adding an alkali to these test formulas wherever possible.

Alan, ideally the way I'd like to test this is to first compare the following:

1) Solution "A" from my series (20g sulfite, 1g Dimezone-S)
2) A solution of 20g sulfite, 1g Metol (adjusted to the pH of solution A)
3) A solution of 20g sulfite, 1g Metol, 1g Dimezone-S (adjusted to the pH of solution A)

At this pH one could then see if Metol and Dimezone are additive, sub-additive, etc. Further tests could then be made adding the third agent (pyro, HQ, catechol, ascorbic acid.

Then again, I seem to have already found a formula which appears to work quite well, giving very low contrast and full film speed. Unfortunately Pyro seems to be preferable to HQ in this application. But more work is required before conclusions can be drawn.

Xmas · Jan 28, 2014

Sodium sulphite is an alkali anyway?

If you want repeatable and have a pH dependency then it may be easier with a pH buffer other wise the metol may be a different pH test...

removed account8 · Jan 28, 2014

Yes sulfite provides the alkalinity in these test formulas so far.

Alan Johnson · Jan 28, 2014

I made pH meaurements :
Sodium sulfite 20g/L........................ pH = 9.5, 9.4
Sodium Sulfite 20g/L +Metol 1g/L........pH= 8.3, 8.4

removed account8 · Jan 28, 2014

I'm confused. Are you saying a plain 2% sulfite solution measured pH 9.5? That seems very high.

Alan Johnson · Jan 28, 2014

pH measured 9.5, 9.4 for 20 g/L seems consistent with the figure of pH=9.7 for 100g/L in "Developing" CI Jacobson 8th ed p67.

removed account8 · Jan 28, 2014

If that is the case, and adding 1g/L each of Dimezone and Pyro doesn't materially lower the pH, this is likely not worth pursuing further. This would be approximately the same working pH as typical carbonate-driven "acutance" developers. Not the direction I wanted to go in at all. I was targetting a much lower pH.

It also means I don't understand how D-76 has a working pH ~8.5 if the acidity of the Metol salt is neutralized by the Borax and what is left to provide alkalinity is 100g/L sulfite.

Rudeofus · Jan 28, 2014

Buffering of Sulfite above pH 8 is very weak, which means anything that's remotely acidic will bring down pH a lot. Look at the numbers I posted for POTA: 8.42. Given this I would rather measure pH before assuming that an additional compound won't have any pH effect.

removed account8 · Jan 28, 2014

I think Gerald once mentioned a type of pH strip or something like that, which is accurate enough for this type of work. Are you familiar with such a thing? I had looked into getting a pH meter a while back, but it was too complicated for me, requiring electrodes stored in buffer solutions, special electrodes which would not be damaged by photographic solutions etc.

Alan Johnson · Jan 28, 2014

I have found Hydrion pH paper to be reliable, it is sold on ebay.
The pH can be reduced with sodium bisulfite but IDK if this would give good enough buffering to be satisfactory.

Rudeofus · Jan 28, 2014

Sulfite/Bisulfite buffering is very weak around this pH, and this is apparently an important property of these low contrast developers. If you want to lower pH of such a developer without affecting its other properties, Acetic Acid would be much better.

@Michael: why do you put up so much resistance against getting a simple pH meter? They are cheap and easy to use, and most likely more accurate than these test strips.

Xmas · Jan 28, 2014

If you want a specific pH you need a buffer pair that will hold that pH before and during process. look up mix weigh it out the buffer will hold the pH.
You may not need a pH meter or strip.

removed account8 · Jan 29, 2014

Rudeofus said:
Sulfite/Bisulfite buffering is very weak around this pH, and this is apparently an important property of these low contrast developers. If you want to lower pH of such a developer without affecting its other properties, Acetic Acid would be much better.

@Michael: why do you put up so much resistance against getting a simple pH meter? They are cheap and easy to use, and most likely more accurate than these test strips.

Hi Rudeofus, I'm only resisting it because it didn't seem that easy to use. I don't know enough about them so I had no idea which one to get. I didn't know what sort of electrodes I needed either - since "standard" electrodes can be damaged by photographic solutions. Combine this with having to mix special buffer solutions to store the electrodes, etc. It was a little overwhelming and I basically gave up on it. I know technically I would really need one in order to do this sort of work properly.

Regarding the test developers, thanks to you and Alan for helping me out with some pH values so far. I knew sulfite was a very weak buffer in this range - which is desirable in a low contrast developer. I was initially surprised the pH of a plain 2% sulfite solution would be nearly as high as that of Borax. I was also surprised a small amount of Metol could lower the pH of the sulfite solution that much, even with the sulfite being a weak buffer. Even more surprising is the fact Phenidone apparently lowers the pH of the sulfite solution significantly in POTA.

I think this is where I need more information (and probably a pH meter) - ie regarding the acidity/alkalinity of developing agents and associated salts. I knew Metol and hydrochloride salts of p-aminophenol etc. are acidic, but naively assumed Phenidones, HQ, Pyro etc. were essentially neutral. Clearly that is not correct. The working pH of POTA should have tipped me off to this, but for some reason it didn't occur to me.

I'm still hopeful I can sort of figure this out. In particular the preliminary Sulfite-Pyro-Dimezone test formula worked very well. The HQ version gave slightly lower speed and higher contrast, but it might be possible to fix that by adjusting the relative concentrations. Still lots of things to try. An ascorbic acid version would be even nicer. Avoiding Pyro would be good.

nworth · Jan 29, 2014

The subject here was how to get a POTA-like developer. The subject developer does have quite low contrast, although considerably higher than POTA. It also has a quite a bit less fog, which is a plus. I notice it also has quite significant stain, which is a little surprising given the amount of sulfite. You might be able to lower the contrast a bit by lowering the pH, but the pyro is obviously active and is inherently a high contrast agent. So is ascorbic acid, for those who want to go that route, although it will not add to the contrast with stain.

removed account8 · Jan 29, 2014

The goal here wasn't really a POTA-like result. It was to get very low contrast (ie N-3 or 4 or "comp", but not anywhere near as low as POTA) developer with full film speed and reasonably good toe contrast without abnormal fog. The test formula with Pyro achieved the desired results (at least with the first test film which was TMax 100), but since Pyro is highly toxic I wanted to continue exploring other options. The HQ substitution gave more contrast and slightly less speed, but this was only a preliminary results. Much experimentation will be required to find more optimal ratios for different superadditive agents.

pH came up as an issue because I wanted a developer which operated in the range 8-8.5, which is likely the case with the test formula. Then I got worried the pH might be too high based on Alan's sulfite measurements but I had neglected to consider the pH-lowering effect of the addition certain developing agents which I had assumed to be neutral. Hence the need for some way to measure pH values.

I'm glad you brought up the stain issue as I forgot to mention that in the second set of tests I posted. It is in fact not Pyro stain (which makes sense given the concentration of sulfite). It appears to simply be an attribute of the film itself. When you examine the developed silver by eye by transmitted light it has a slight orange colour at high densities (no colour is noticeable at low or mid densities). The colour cast doesn't have much of an effect even with blue filtration except at the highest densities where the added density is still proportionately quite small relative to what one observes with a staining developer.

I had first attributed this to a small amount of stain from the Pyro, but it didn't make much sense to me. When I omitted the Pyro, I got the same effect. When I replaced the Pyro with HQ, again the same effect. And most importantly, with XTOL I observed the same result.

Gerald C Koch · Jan 29, 2014

Michael, Here is another developer formula you might be interested in.

Peckham Fine Grain Developer

This novel formula appears in the British Journal of Photography. The author
states that Metol with catechol and borax play an important and unusual role.
The borax accelerates the Metol, but it heavily restrains the catechol. Good
balance between these opposing forces removes the need for potassium
bromide or any other anti-foggant."

Distilled water (50°C) …………………………………………… 750 ml
Sodium sulfite (anhy) ……………………………………………… 0.35 g
Catechol† ……………………………………………………………………………… 0.42 g
Metol ………………………………………………………………………………………… 2.6 g
Sodium sulfite (anhy) ……………………………………………… 4.6 g
Borax ………………………………………………………………………………………… 0.8 g
Sodium bicarbonate ……………………………………………………… 28.0 g
Sodium sulfite (anhy) ……………………………………………… 113 g
Distilled water to make ………………………………………… 1.0 l

Usage

Use full strength. Average development time is 7 to 10 minutes at 21°C with
continuous agitation.

Notes

The formula has been converted to metric measurements.

Cyril Peckham, British Journal of Photography, Dec 26, 1969.

Murray Kelly · Jan 30, 2014

Michael, I direct your attention to Dave Soemarko's LC-1B. It is designed for continuous tones on lith film which is no mean feat.

Metol 4g
Sod sulphite 120g
HQ 4g
Sod bisulphite 30g
aq ad 1L

Dilute from 1:6 to 1:12 5 to 10m with continuous agitation at 75F

I measured the pH at 7.3.

removed account8 · Jan 30, 2014

Thanks for these additional formulas to test. I was not aware of either of them.

Gerald - this formula is particularly interesting as it is the only one I've seen which purposely uses the restraining effect of borate alkalis on ortho/phenol agents like catechol. Haist mentions borates react with these compounds (catechol, pyro, etc.) to form a reaction product of weak developing potential. It always made me want to ask Hutchings if he was aware of this when he formulated PMK with Metaborate, whether this played a specific role in his choice of that particular alkali, etc.

Murray: I'll try to run some experiments with the formula you posted above and see how it goes. However I suspect if it was formulated for continuous tones on litho film it falls more under the category of document film developers which tend to produce exceedingly low contrast (ie too low) and relatively low film speed when used with general purpose films. The idea behind these particular experiments was to find a middle ground - ie a developer for general purpose films giving greatly reduced overall contrast and full film speed with good toe contrast, while retaining a relatively linear curve, low fog, and without the granularity typical of conventional general purpose "compensating" developers relying on dilution and high pH.

Xmas · Jan 30, 2014

Gerald C Koch said:
Michael, Here is another developer formula you might be interested in.

Peckham Fine Grain Developer

This novel formula appears in the British Journal of Photography. The author
states that Metol with catechol and borax play an important and unusual role.
The borax accelerates the Metol, but it heavily restrains the catechol. Good
balance between these opposing forces removes the need for potassium
bromide or any other anti-foggant."

Does that mean that potentially you could control the contrast by changing
the borax concentration?

Alan Johnson · Jan 30, 2014

The catechol-borax compounds have known formulae given in equations 4 and 5 below.
They seem to be present in very low concentrations in the developer formula given.
Borax is stated to form complexes with orthodiphenols only, ie not with pyro.
http://www.jbc.org/content/227/1/473.full.pdf

Shawn Dougherty · Jan 30, 2014

Michael R 1974 said:
The formula is:

20g sodium sulfite
1g Pyrogallol
1g Dimezone-S
--------------
1L

A H&D curve for 35mm TMX is attached. Development time was 10:00 at 68F, without any fancy routines. Basic inversion agitation for 30 seconds initially, followed by 10 seconds each minute. There appeared to be some orange-ish imagewise stain at high exposure densities so I measured using white light, blue and green. Preliminary observations:

-Marked toe contrast and full film speed (equivalent to normal development in XTOL)
-Equivalent contrast of ~N-3 or more in ZS terms
-Uniform development
-Normal fog level (same as XTOL)

I have been following this thread with great interest, the simplicity of the formula is quite appealing to me. I've settled on D23 1+3 for my N-, N, and N+ developement with both 4x5 sheet film and 120 roll film. (Yes, 1+3 can expand the negative a least a modest amount though the times do get rather long) I have not yet had a need to develop N++ or extreme N+ but I'm confident it can be done by moving to 1+1 or maybe even straight D23.

I have also not had need for anything besides a reasonable N- development lately, just the subject matter I have been working with I suppose, though I plan to get back to more high contrast situations in the near future. In the past I used very dilute Rodinal to achieve more extreme N- development (N-2, N-3... or whatever they really were) but I am trying to stick with developers that I can mix easily at home and work well with continuous agitation (BTZS style tubes in water) for my 4x5 negs. I also would greatly prefer that the film "held its speed" with the more extreme N- development (as this formula seems to thus far). In the past I have needed to place my shadows up on Zone 5 as part of the process.

I just priced 100g of Pyrogallol and 100g of Dimezone S at Photographers Formulary (I have lots of Sodium Sulphite) and can have them shipped to me for a total of $60.38. That seems pretty reasonable.

I wonder, how much solution do you suppose is required for 1 sheet of 4x5? I like to use at least 100ml of solution per sheet in my homemade tubes, they will hold as much as 200ml. I also wonder if you would expect much change based on the use of continuous (but gentle) agitation such as in my BTZS style tubes?

While I'm not the biggest fan of staining developers in general (they can be alittle harder to see through when contact printing) the set of curves in (there was a url link here which no longer exists) are very encouraging, especially the toe contrast. I'm not sure how much more tinkering I'd really require. It would seem to me that an N-2 or N-3 scene shot at near box speed and developed this way would be very printable... and I'm always willing to do some work come printing time.

P.S. Speed loss would be the reason I'd look to something other than D23 for my more extreme N- negatives.
P.P.S My use of the term extreme and maybe some other references may not be completely accurate but I believe they are directionally correct (and at the very least I believe MichealR knows what I mean my them )

Xmas · Jan 30, 2014

Alan Johnson said:
The catechol-borax compounds have known formulae given in equations 4 and 5 below.
They seem to be present in very low concentrations in the developer formula given.
Borax is stated to form complexes with orthodiphenols only, ie not with pyro.
http://www.jbc.org/content/227/1/473.full.pdf

hi Alan
That is useful thanks a lot I need to print it out and think.
I may try the published formula next.
Dont like handling pyro.

Noel

removed account8 · Jan 30, 2014

Shawn, re stain (see post #41) it turns out it was not Pyro stain (which makes more sense) so although a lot more testing is required here, I think we can call it a non-staining/tanning developer.

The other thing is, while the curve for that first formula looks quite promising (pretty much exactly what I wanted), I haven't printed any of the negatives yet (I hope to get to that in the next few weeks) so I can't comment with certainty regarding uniformity (it looks good by eye but who knows until you print), nor can I say anything about graininess (not that this would matter with LF anyway especially since you're contact printing, but still).

Since this was only a first cut at a formula, there may be ways to get the same results without having to resort to Pyro per se.

Since you raised the question about continuous agitation, it is definitely something worth exploring with a shorter development time. Another thing I was going to try is a more dilute variant, which would make for longer development times, which could help keep the development time a little longer with continuous agitation.

Regarding solution volume, in my first tests I used 375ml of the solution in a two-reel tank to develop 1 roll of film, which is more or less the equivalent of 4 sheets of 4x5. So my preliminary guess is even at 100ml/sheet you've got plenty. Remember, this is not a very dilute developer in terms of developing agent concentration. It's the opposite approach to the highly-dilute minus development technique. Here instead of diluting a general purpose developer, we instead use a fairly high concentration of an inherently low contrast developing agent (Phenidone derivative) with the addition of a secondary superadditive agent to both build more contrast and help "stabilize" the Phenidone.

If you end up trying it I'd welcome any feedback. In the meantime I'll keep working on this and posting to this thread - and yes I think I'll end up getting a pH meter after all....

Shawn Dougherty · Jan 30, 2014

Michael R 1974 said:
Shawn, re stain (see post #41) it turns out it was not Pyro stain (which makes more sense) so although a lot more testing is required here, I think we can call it a non-staining/tanning developer.

The other thing is, while the curve for that first formula looks quite promising (pretty much exactly what I wanted), I haven't printed any of the negatives yet (I hope to get to that in the next few weeks) so I can't comment with certainty regarding uniformity (it looks good by eye but who knows until you print), nor can I say anything about graininess (not that this would matter with LF anyway especially since you're contact printing, but still).

Since this was only a first cut at a formula, there may be ways to get the same results without having to resort to Pyro per se.

Since you raised the question about continuous agitation, it is definitely something worth exploring with a shorter development time. Another thing I was going to try is a more dilute variant, which would make for longer development times, which could help keep the development time a little longer with continuous agitation.

Regarding solution volume, in my first tests I used 375ml of the solution in a two-reel tank to develop 1 roll of film, which is more or less the equivalent of 4 sheets of 4x5. So my preliminary guess is even at 100ml/sheet you've got plenty. Remember, this is not a very dilute developer in terms of developing agent concentration. It's the opposite approach to the highly-dilute minus development technique. Here instead of diluting a general purpose developer, we instead use a fairly high concentration of an inherently low contrast developing agent (Phenidone derivative) with the addition of a secondary superadditive agent to both build more contrast and help "stabilize" the Phenidone.

If you end up trying it I'd welcome any feedback. In the meantime I'll keep working on this and posting to this thread - and yes I think I'll end up getting a pH meter after all....

Thank you, Michael.

The lack of pyro stain (and small amount of whatever it happens to be stain) is something I missed and a positive as far as I'm concerned.

The short times are not ideal as far as even development goes but I could always up the amount to 200ml in each 4x5 tube which would cover more surface area and might help... and 10minutes (or maybe 8'30" for continuous) is not really all that short... especially with rotary processing. Hmmmmm.

I'm not quite ready to pull the trigger yet but if / when I do I will certainly let you know what I find, at least so much as my eyeballing of negatives and prints can tell. In the meantime I will keep track of your progress here.

Thanks again and good luck with the pH meter!

A very low contrast, low pH, full speed POTA variant

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