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Perceptol & The Microdol Substitute Formula.

Ian Grant

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Yes but do these reactions take place that quickly ? After all we know that D76/ID-1 and similar developer need 24 hours for the solution to stabilise and are more active if used immediately.

Rodinal uses the free base of p-Aminophenol, while MQ devs use Metol which is a sulphate form of N-methyl p-Aminophenol and the Rodinal reaction is taking place in the presence of a very high level of sulphite.

Whether the true time needed is actually a couple of weeks might well be doubtful but that seems to be the timespan chosen. So Rodinal isn't the only developer that needs to age & stabilise but perhaps it needs longer.

Ian
 

Photo Engineer

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Well, that is part of my point.

HQ -> Q + SO3 -> HQMS and this is a 2 step reaction. It is an oxidation and then a substitution on a benzene ring. These are generally far slower than acid base reactions which can go explosively they are so fast (generally). So, my point is that it is probably not the reaction of acid + base, but something else.

So, you are correct, but that poses the quesiton more strongly. Something else is going on, not acid base neutralization or equillibration. Instead, there is probably a redox reaction which is quite slow.

PE
 

Kirk Keyes

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Would it, with all the sulfite in there? The sulfite would afford the pyrogallol protection as well.
 

Photo Engineer

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Kirk;

It depends on Kinetics and Thermodynamics.

Which has the highest reduction potential and which has the fastest reaction.

PE
 

Kirk Keyes

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Right. But...

Wouldn't the pyrogallol also follow a similar path that HQ does with sulfite? As you posted above:
HQ -> Q + SO3 -> HQMS

The pyrogallol should be forming a semiquinone and then quinone like HQ, so wouldn't sulfite be doing that with pyrogallol, and that could help keep the solution clear and colorless for a while.
 

Kirk Keyes

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Getting away from Perceptol for a second - Is anyone ever going to find out the results of Dr. Schneour's analysis of Rodinal? Or is that going to remain a secret?
 

Photo Engineer

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Kirk;

Here are some thoughts.

If the reaction of SO3= with Oxygen is slow at high pH compared to the reaction of pAP or PG at the same pH, then either developer would go first before Sulfite ion reacts. In fact, that was my first question. What happens to the redox potential of Sulfite as a function of pH? If it goes down, and that of the developing agent goes up, then Sulfite becomes less effective as a scavenger of Oxygen than the developing agents themselves.

OTOH, PG has 3 OH groups and only 2 sites for Sulfite to react whereas HQ has effectively 4 sites for a similar reaction. Now this assumes that PG reacts. Since those 2 sites in PG are meta to the central OH, the activity of the sites is probably low. I would have to look this all up, really to be sure. It is just conjecture right now from old organic chemistry. My guess is that PG would react slowly with SO3= compared to HQ when both developing agents become oxidized.

This leaves open the question or rather theory that something else is happening over the short term in Rodinal type developers. And, I can see hints of this when I mix Rodinal type formulas and Metolal type formulas.

PE
 

Ray Rogers

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Getting away from Perceptol for a second - Is anyone ever going to find out the results of Dr. Schneour's analysis of Rodinal? Or is that going to remain a secret?

Getting away from Perceptol...While staying on the topic of Rodinal?

I would like to get clarification on the "Formulas" Ian referrs to a few posts back.

Which formula is Ian calling the "Original Rodinal" in post #74?
Is the formula for "Calbe R-09" given anywhere... under the "Calbe" name?
Can someone provide a ref to the nitrogen formula/comment in post #74 ?

If these all refer to actual published formulas, I can't seem to locate them in the long list Ian published here a while back.

:confused:

Perhaps Dr. Schneour could shed some light on this!
 
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Ian Grant

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Much of it was in the thread Modern Rodinal substitutes.

Agfa and Dr Momme Andresen himself wrote about Rodinal in the 1890's & early 1900's, as did contemporaries.

What some call "Traditional Rodinal" was first published in an Agfa book written by Andresen himself. It doesn't claim to be Rodinal type.

It uses p-Aminophenol Hydrochloride, and in other Agfa books of the time they state Rodinal contains p-Aminophenol and is a proprietary Patented formula, the next formula listed (more than one book) is for a developer containing p-Aminophenol Hydrochloride. Agfa always make a very clear distinction between the free base & the hydrochloride, that's in books published by the Berlin Aniline Company, New York (Agfa USA), Agfa themselves in German handbooks, and articles by their UK Importer/Distributor Chas. Zimmermann

Contemporaries of Andresen, Desalme etc tell us that to make a "Rodinal type" developer first you first need to dissolve p-Aminophenol Hyrdrocloride and add Carbonate precipitating and collecting the "free base". Ilford released there version of a "Rodinal type" developer "Certinal" in 1908/9, Kodak had a version as well "Kodinol" but the only official Kodak references I have to it are Data Guides from the 40'/50's. and it appears to have been a solely European product.

Kodak Research, Rochester and Harrow were formed when Kodak bought the UK company Wratten & Wainwright, and both were run by former Wratten Directors/Senior research staff. Mees & Sheppard had worked on the properties of developing agents including p-Aminophenol while at Wratten, (there's published work), so Kodak could easily have introduced Kodinol quite early in the UK.

Agfa have always said they've never published any of the Rodinal formula, but there are plenty of indications in various sources to allow us to deduce a probably substitute

So in the article "Modern Rodinal Substitutes" I suggested how I'd make substitutes for Rodinal and detailed why I'd chosen those particular formulae.

Ian
 
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Ray Rogers

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OK, so you were not thinking of any specific formulas when you wrote those words...

Sorry everyone.
I appreciate Ian's comments - but the meaning of "original" & "modern" seems fuzzy to me. If they referr to specfic known formulas - I think it is best to use proper nouns or to just give the actual formulas; "original" & "modern" are highly subjective.

Calling Calbe R-09 formula a "pre-WW II" formula is confusing to me as well, since, as I understand it, it can also be called a WW-II formula.

It is likely that some of the confusion comes from the fact that the developing solution was named after the developing agent, something which isn't all that common, thank goodness!

As for as Nitrogen, was there any official AGFA or Calbe for that matter mention or discussion of this?

Maybe I am guilty for not reading everything here on apug - again.

Sorry if I am lowering the curve, but for example with nitrogen, the only thing I could quickly turn up were a few suggestions and not documented Agfa policy. Perhaps there are patents, or inside info, but whatever, I am just trying to follow the conversation not stall it. Please continue!

 

Kirk Keyes

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Since those 2 sites in PG are meta to the central OH, the activity of the sites is probably low. I would have to look this all up, really to be sure. It is just conjecture right now from old organic chemistry.

You're better at flipping electrons than me! I'm just an analytical chemist! ;^)
 

Ian Grant

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Calling Calbe R-09 formula a "pre-WW II" formula is confusing to me as well, since, as I understand it, it can also be called a WW-II formula.

That's how the distributors describe it, as made to the pre War Agfa formula. Perhaps there were shortages during the War Suphite needed for military products.

As the full formula have never been published but we know there have been evolutionary changes its hard to name them.

I tried to make things quite clear in the very first post. But it ain't easy


As for as Nitrogen, was there any official AGFA or Calbe for that matter mention or discussion of this?

Agfa used to have something on their website, they had a long article on 100 years of Rodinal at one time, which I think they also released as a Press Release as well as putting it online. They used to mention the use of Nitrogen in literature too.

This one though has been written about a few times so should be easy to find & verify.


I have to go back and re-read too I did a lot of research, and have turned up far more since, that totally backs up what I wrote in the first post.

I also did a lot of calculations on the reaction quantities particularly of the p_Aminophenol, Potassium Metabisulphite and Hydroxide reactions. This one made slightly more complex (but not difficult) because the Metbisulphite forms Sodium and Potassium Sulphite, when they used Sodium Hydroxide.

I still have a lot more data to go through, but there's alimit on how much time I want to spend on Rodinal

Kodak have a wealth of information on these developers, they have/had all Desalme's writing on similar developers, the free bases and salts, I'd guess Meees & Shepperd collected the information while at Wratten as they worked on p-Aminophenols and other developing agents in the UK.

Gerald Koch seems to have disappeared, he would maybe have been able to shed some light on Kodak's commercila "Rodinal" type high concentration p-Amininophenol developer "Kodinol". But I'm not sure who can help I think he and I discussed this before in an exchange abut Kodak's "Kodelon" developing agent. This is stated to be p-Aminophenol Oxalate which maybe what's used in Kodinol, but I have a photograph of a bottle of Kodak Kodelon which quite clearly states p-Amininophenol Hydrochloride.

That's the kind of woolly areas we delve into, no-one has really done any research at all into developer history.

I was told in a previous post (different thread) not to bother with pre 40's developer formulae. While there's a grain of sense you actually need to go back to the roots. Most of the early formulae are very similar but there are some milestones and sidetracks, but nearly all modern formulae come from those early roots.

So I'll keep plodding away, there were other early alternatives.

PMK is just a very early Pyrogallol/Metol developer used much more dilute with a different alkali

We don't always need to re-invent the wheel just find the ones that fell off photographers carts and adapt & make them fit modern films.

Ian
 

lensmagic

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I would like to go back to the original question--which I think remains unanswered:

Has anyone tried comparing `Edgar Hyman`s Microdol substitute formula with Ilford Perceptol? If so, did you notice any difference between the packaged product and the home made developer?
Edgar Hyman’s Microdol Substitute Formula:
Metol....................................5 grams
Sodium Sulphite, anhydrous........100 grams
Sodium Chloride (iodine-free)... 30 grams
Water to make.......................1 litre of stock solution.

For me this is not an idle question. I use this formula, which is also Troop's Film Developing Cookbook formula. I dilute 1:4 with water and develop 100TMX. What am I missing out on by not using Microdol X or Perceptol??
 

Ian Grant

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I've tested the formula, it worked well and as expected - much finer grain, drop in effective EI etc, my reply is on the first page of the thread. Since Kodak re-formulated Microdol as Microdol-X and Ilford replaced ID-48 with Perceptol B&W films have changed significantly and those I've used are far less prone to Dichroic fog.

Ian
 
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Keith Tapscott.

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Thanks for bringing the thread back on topic.
I am sure that if benzo-resorcinol and chloro-resorcinol worked as an anti-staining agents back in the 1960`s, then they will still have some practical use for todays B&W films even if Kodak have moved onto something else since then.
It seems to me from the two patents by R.W Henn for Kodak, that films which contain more silver-iodide are the one`s that are prone to dichroic fog.
If I can make my own Perceptol, then I am not restricted to having to mix 1 litre of stock solution at a time.
My main developer is D-76 diluted 1+1, but I have seen prints from Pan F Plus negatives developed in dilute Perceptol that are truly outstanding.

Anti-Stain agent.
 
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Keith Tapscott.

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From the patent by Richard W Henn:
"The silverstain or scum, usually referred to herein simply as stain, is more likely to be produced in `USED` photographic developers than in fresh photographic developers and becomes increasingly pronounced with extended development times".

As most people don`t reuse or replenish developers these days, I don`t see the point about finding an anti-staining agent, particularly if the developer is going to be diluted and used as a one-shot working solution which is how I will use it.
If anyone has tried the formula and experienced stain or fog, please report your findings on this forum. I think this is unlikely to happen.

Thanks to everyone for their input and for raising the possible problems of dichroic fog and unwanted stains, which is very much appreciated.
 

newcan1

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I am by no means a scientist, so I apologize if this question is lame. I have read through this now somewhat old thread. Would a restrainer such as benzotriazole assist in retarding dichroic fog?
 

Anon Ymous

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I am by no means a scientist, so I apologize if this question is lame. I have read through this now somewhat old thread. Would a restrainer such as benzotriazole assist in retarding dichroic fog?
I'm not a scientist either, but I've used this formula with TMX, 400TX, APX100 and Rollei Retro 80S. I never had a problem with dichroic fog. The results were always very nice.
 

newcan1

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I want to try it with some 1970's era ANSCO film originally rated ISO 400. I have no idea if fog will be a problem, but I am curious to know if BZT would help if it is.
 

newcan1

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PE, do you regard 1970's era ANSCO film as "modern"? And at any event, would BZT help with dichroic fog?
 

newcan1

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And one more question: Could I use potassium chloride instead of sodium chloride?