MCM-100 developer problem

[newcan1]

I posted a while ago about some Ansco Super Hypan film that I was experimenting with. I was able to get decent results using D76, but very grainy (and not very nice grain). I decided to try MCM-100, which I mixed from raw chemicals purchased from the formulary.
I had thought that this film would be well suited for MCM-100; it's a fairly old-school emulsion from the 70's. I was getting acceptable results at ISO 80 with D76, albeit with noticeable base fog. I shot a test roll at ISO 50, 100, and 200, and developed in the home brewed MCM 100, at about 70 degrees for 18 minutes. I was very disappointed, The roll was extremely under-developed. Now the question is why.
I am certain I mixed the chemicals per the formula. I had just received the chemicals from the formulary a few days earlier. The catchetol is white in color, the PPD is a pale brown. The formula says "do not use the monohydrate of trisodium phosphate." The CAS number of the stuff I got from formulary is the do-decahydrate version. The formula just calls for trisodium phosphate, crystalline. I know there are various versions with differing amounts of water molecules attached.

Is it possible that I should have used more trisodium phosphate than the formula calls for, as the stuff I used was the do-decahydrate version? Someone please help! I was hoping that this film and MCM-100 would turn out to be a marriage made in heaven, but perhaps not.

 

[Rudeofus]

If I look at the Formulary product here, CAS number 7601-54-9 is stated in the SDS linked from that page. Wikipedia page for Trisodium Phosphate confirms, that this CAS number refers to the anhydrous form of Trisodium Phosphate. Strangely, no monohydrate form is listed in Wikipedia page for Trisodium Phosphate.

Therefore I wonder how you were able to obtain Trisodium Phosphate Dodecahydrate from Formulary. If you really did get the dodecahydrate, then I guess we know what went wrong. If not, you might think about trying their packaged version of MCM-100. If their version doesn't work well either, at least you know it's not you but the combo of this film and MCM-100.

 

[newcan1]

Well the jar is marked CAS No. 10101-89-0 which is the dodecahydrate. The formula simply calls for crystalline, but it doesnt say which - 6H20, 8H20, or 12H20. I could increase the triphosphate a bit, based on a molecular weight comparison with 6H20, but that would be guessing. Better than throwing the brew away though as I have only used it once, and I have tons of this film.

 

[newcan1]

A quick search on the internet indicates that a number of companies selling triphosphate "crystals" are indeed selling the dodecahydrate.

 

[Alan Johnson]

The formula here calls for the anhydrous version:
http://www.lostlabours.co.uk/photography/formulae/developers/devMeritol.htm

 

[newcan1]

Well the molecular weight of the anhydrous is 163.94, and of the dodecahydrate is 380.12. My formula called for 6.9g of "crystalline". (380.12/163.94) X 2.9 = 6.72g, so my 6.9 isn't far off from what is called for in the above referenced version of the formula. That can't be the problem.

The PPD I received was a medium reddish brown. I wonder if it was too oxidized to be reliable? I have not used ppd before so I don't know how much discoloration is acceptable. Or maybe the film doesn't like this kind of developer.

 

[Rudeofus]

Which dev times did you use when you got acceptable results with D76? Given the age of your film, I would expect vastly increased development times to reach normal contrast.
Here is how I would approach this:

1. Assume that MCM-100 will work. It is a developer like many others, there is nothing substantially different with PPD+Catechol compared to Metol+Hydroquinone
2. Find out whether your developer is too inactive or whether your film needs more development. Develop for at least twice as long and check whether base fog builds up. If double the development time does not show fog with our film, developer activity is likely too low. If you see fog, then you now know a good development time for your film.
3. If activity is too low, raise pH of your developer by adding Sodium Hydroxide or Trisodium Phosphate until your film shows fog after 20-30 minutes of development.

BTW There's a nontrivial chance that your PPD is not free base as prescribed by the formula but some salt (typically Sulfate or Chloride) - this may have unexpectedly lowered pH of your developer.

 

[newcan1]

Rudeofus, thanks for this reply. I am going to develop for a longer time, as you suggest, and if results are still poor, I will add more trisodium phosphate. I am still a bit troubled though that the PPD is medium brown. I only just bought it; I hope it isn't too oxidized. Its CAS number is 106-50-3.

Interestingly , with three different ultra fine grain developers, similar underdevelopment has occurred (MCM100, Rayco ultra fine grain, and home brewed perceptol). With D76d, development times were not too far off normal, if I recall correctly. But I am beginning to notice that with outdated films, not only do they tend to lose speed, but they often also take longer to develop.

I think I am going to develop the next test roll for 40 minutes.

 

[Ian Grant]

Assume that MCM-100 will work. It is a developer like many others, there is nothing substantially different with PPD+Catechol compared to Metol+Hydroquinone.

That's a flawed assumption Meritol which is PPD & Pyrocatechin gives finer grain and better sharpness compared to an MQ developer like D76/ID-11. Pyrocatechin on its own is the basis of some fine grain developers.

Perhaps the OP should read the last paragraph in the link Alan Johnson gave:

The formula here calls for the anhydrous version:
http://www.lostlabours.co.uk/photography/formulae/developers/devMeritol.htm

Important Note: It is emphasised that the backing on certain roll films has a restraining effect on Meritol development, hence such films should be given a preliminary soaking in plain water for about three minutes with agitation. This treatment does not affect development times.

This information is from Johnsons of Hendon the manufacturers of Meritol, technically still trading as Johnsons Photopia they are the oldest photographic company in the world and supplied chemicals like Silver Nitrate to Fox Talbot.

It maybe important to use the anhydrous form of Tribasic sodium phosphate, I know that in one of his formulae Geoffrey Crawley insisted on a particular form of Sodium Carbonate. This can be a purity variation in manufacturing where a stated form is a mixture.

Perhaps the extreme example is Sodium Metabisulpite and Sodium Bisulphite. Pure Sodium Bisulphite is unstable and has a very short shelf life it is only available as Analytical Reagent Grade and very expensive. What's usually sold as Bisulphite is 60-90% Metabisulphite the rest Bisulphite, where as Metabisulphite is 99% Metabisulphite.

So with a small quantity of Tribasic sodium phosphate (anhyd) in a litre a variation in quality using a crystalline form could be quite significant. From memory the issue with the Carbonate Crawly mentions was the proportion of Bicarbonate.

Ian

 

[newcan1]

The film I am experimenting with is 35mm, but the Film Developing Cookbook (which references the crystalline trisodium phosphate in its formula) suggests a pre-soak in 5% sodium sulphite solution or water. I just did another test film, and pre-soaked for five minutes in 5% sodium sulphite solution. I developed for 40 minutes. I had shot the test images at 50, 100, and 200 ISO. The 50 ISO image has excellent density; the 200 ISO may be printable but is thin (based on visual inspection). ISO 100 is a bit thin. There is some base fog, but not as much as when I develop in D76 (where the optimum ISO seems to be around 80). Thus I think that the film is still a bit underdeveloped. Based on Rudeofus's and Ian's comments, I guess my next step is to increase the amount of trisodium phosphate. I am guessing that when I get the formula/dev time optimized for this film, it will shoot at an ISO around 100. Looking at the negatives through a loupe, grain is smaller than with D76, and resolution appears to be higher. I may also try the Germain fine grain formula on this film as I suspect that the addition of metol will lead to shorter development times.

I am grateful for all the comments you have all posted.

 

[Rudeofus]

That's a flawed assumption Meritol which is PPD & Pyrocatechin gives finer grain and better sharpness compared to an MQ developer like D76/ID-11. Pyrocatechin on its own is the basis of some fine grain developers.

Each combination of development agents will have somewhat different properties, but they are all close enough that you won't be able to name a film product which will develop in one developer and not in the other. As we have seen, MCM-100 works quite well with this old film if you give it enough time, and some added Trisodium Phosphate will speed it up enough to reach more reasonable development times.

 

[newcan1]

I posted this separately, but should I increase PPD? does this look oxidized to the point of reduced activity?

 

[Rudeofus]

It will be difficult to determine the real purity of your PPD flakes with amateur means. The not cheap but cheapest way to see whether PPD quality is an issue is to get some fresh PPD from a known good source and compare results.

 

[newcan1]

Well I got this from Photographer's Formulary, I assume they know what they are doing, but it looks a bit oxidized. I will do another test of this GAF film tomorrow, increasing the trisodium phosphate from 6.9g/L to 10g/L. If development time is still too long, I may increase the PPD by say 25% in case oxidation is a factor.

 

[Ian Grant]

I posted this separately, but should I increase PPD? does this look oxidized to the point of reduced activity?
View attachment 206960

i have some 30+ year old PPD and it's still a white powder, \i can't add more.

Ian

 

[Rudeofus]

PPD oxidizes to all kinds of brown colored goo/polymers if conditions are right/wrong. One thing you could look is whether brown discoloration is only on the surface or throughout the flakes. If only the surface is brown but the interior is white, then the bulk of the PPD may still be unharmed. NOTE: PPD is crazy toxic and can trigger nasty allergies, please be extremely careful when handling this stuff!!

 

[Ian Grant]

NOTE: PPD is crazy toxic and can trigger nasty allergies, please be extremely careful when handling this stuff!!

That's why it's still used in hair dyes. I had a reaction to it last year despite using gloves and having no direct personal contact with it, in a developer I'd have far less risk of exposurre.

Ian

 

[Rudeofus]

#in a developer I'd have far less risk of exposurre.

I am not that much worried about it being used in a developer. We already have procedures in place to not touch developer for its alkalinity alone. What I was worried about was people making experiments with PPD powder, there is much more interaction with the compound and the dust it produces, and the likelihood of someone touching PPD is much greater under such circumstances.

 

[newcan1]

I took a flake in some tweezers and cut it with scissors. It was light brown throughout. I may have to experiment with the quantity in the developer, although I have used CD4 in similar condition that seems to work OK in color development.

 

[newcan1]

OK, having increased the trisodium phosphate from 6.9g to 10g, my test of this showed no discernible difference in density compared to the last test. My next - and probably final - test will be to increase PPD by 50% in case oxidation is a problem. Other than that, the only other variable I can think of is that the film just needs a longer development time.

 

[Rudeofus]

From your input I see that apparently MCM-100 already operates at a pH at which further increases in pH will not increase developer activity. If the flakes are brown throughout, then your PPD has not darkened from old age, but was apparently quite impure to begin with. Since I don't think that any credible vendor would ship a product with >20% impurities, I would conclude that your PPD is fine and that your film simply needs vastly increases development times with MCM-100. That said, increasing PPD and Catechol will certainly increase activity of MCM-100, and since shaking a film tank for 40 minutes can become boring over that, increasing PPD might be a good course of action.

You could also consider adding PPD and Catechol in equimolar amounts, since at least some sources claim that the superior properties of MCM-100 stem from a PPD-Catechol complex.

 

[newcan1]

Rudeofus, interesting what you say about adding PPD and Catechol in equimolar amounts. That is expressed to be how MCM100 is formulated - the equimolar amounts are the functional equivalent of Meritol. But the formula calls for 7g of PPD and 9g Catechol. My PPD is CAS No. 106-50-3, and a Mol calculator gave it a molecular weight of 108.14. The catechol is CAS 120-80-9 with MOL of 110.11. If their weights are so close, then the formula would be closer to 7g of each (or 9g of each). Do I have something wrong here?

This is making me wonder if the legendary "777" formula is 7g of each of metol, PPD and catechol, but that's another matter.

 

[Rudeofus]

There are two interactions between PPD and Catechol: one is that they are claimed to form an 1:1 complex, the other is that they are a superadditive developer combo, i.e. Catechol will reduce oxidized PPD back to its original state. The second type of interaction is likely why there is more Catechol than PPD in this formula: the Catechol is actually used up (through development action and by aerial oxidation), while PPD amount stays nearly constant until Catechol runs low.

No idea about the composition of Harvey's 777, and too little experience with it (actually none at all) to warrant a guess.

 

[newcan1]

I think I will do one more adjustment of the MCM-100 formula, with 10g of trisodium phosphate dodecahydrate, 12g of pyroctachin, and 9.3g of PPD. I am going to develop for one hour. Will report back here when done.