4-Hydroxy-m-phenylen-diammoniumdichlorid

[Bertil]

I have a bottle of 4-Hydroxy-m-phenylen-diammoniumdichlorid krist. (C6H10Cl2N2O) that I got with some other raw photo chemicals, but I haven't been able to understand what it is (not a chemist!). Probably some developing agent (light-sensitive according to the label; produced by E.Merck, Darmstadt and "Gesundheitsschädlich"). Anybody who knows what it is and what I can use it to??
//Bertil

 

[Ian Grant]

It looks at first glance like a derivative of PPD, a colour developing agent, the problem is that there are various ways of writing these compounds so it's quite difficult to tell.

But as Alessandro says it could be Amidol which is normal written as 2:4-diaminopheol hydrochloride.
Ian

 

[Bertil]

Thank you for your suggestions, Alssandro and Ian. I wasn't totally surprised by the suggestion amidol, since the guy who many years ago was involved with these chemicals often talked about trying Edward and Cole Weston's recipe for a Amidol paper developer. But according to Wikipedia: "Amidol is a colorless crystalline compound with the molecular structure C6H3(NH2)2OH". It seems to be no Cl in this formula at all. Could there be different versions of amidol?
That it is a colour developing agent, that you suggest Ian, would surprise me somewhat, since he (or those) who had their hands on these chemicals never worked with anything but B/W processes, as far as I know. Maybe they tried to get hold on amidol but got something else.
I'm myself interested in an amidol developer and recently bought 25g at Silverprint. This Silverprint amidol (without chemical formula) looks different, more like dark grey "crystals", the stuff in my (C6H10Cl2N2O) bottle looks more like dark grey smooth powder. But perhaps I should try and see if it works like amidol?
//bertil

 

[Ian Grant]

Read it again, Wikipedia says that photographic Amidol is the dihydrochloride form

If you were to look at the structure of PPD hydrochlorice and Amidol you'd see they only differ slightly, you have got Amidol, it's just I've never seen it written that way before, and can't find a reference that calls it 4-Hydroxy-m-phenylen-diammonium dichloride.

Ian

 

[Bertil]

Thank you Ian! I'm probably just too ignorant in chemistry to fully understanding what I read, just looking and comparing two formulas, sorry!

By the way #1: since I now have a whole bottle (100g) amidol (!!) do you, or anyone else, have some good working formula for an amidol paper developer. My Edward Weston formula contains potassium bromide as anti-fog (as other formulas I have seen), but also a "BB Compound" - the only thing I know is that it contains benzotriazole and that it is not sold anymore; Cole's formula contains no benzotrazole, but He adds citric acid in order to keep the solution clean.
I assume that by adding benzotriazole you can control print tone and make it somewhat colder; is it reasonable just to make a 1% solution and trying adding some 10 ml in steps (a procedure suggested in a recent thread about how to get a cool tone developer)?

By the way #2: I also have 1 kg Potassium pyrosulfate (K2S207); what is this stuff normally used for in photo chemistry (have no formula, I think (sic), that uses it)?

//Bertil

 

[Kirk Keyes]

If the bottle is not too old, look for a "CAS" number, as these are used to identify individial chemicals. They take the form of 3 numbers separated by hyphens. They came up with the CAS system as molecular formulas can be the same for a multitude of different compounds. The CAS for amidol is 95-86-3.

This site: http://www.chemindustry.com/chemicals/749918.html
lists amidol as a synonym for 4-Hydroxy-m-phenylene-diammonium dichloride

 

[Bertil]

Kirk, thanks for this link! Seems very useful. Also, now understand that potassium pyrosulfate is also named potassium metabisulphite, which sounds more familiar, perhaps I will find use for it in some way. I start realize the possibility of learning a great deal about photo chemistry from this excellent forum/site and all good links, it just takes some time! Thanks!
//Bertil

 

[drazak]

Bertil;

Potassium metabisulfite can be used to adjust the pH and buffer characteristics of a developer. In water it has a basic pH, but it's also amphoteric, creating a very nice buffer.

Ben

 

[nworth]

Another name might be 2,4-diaminophenol hydrochloride, which is amidol.

 

[Ian Grant]

Another name might be (there was a url link here which no longer exists)

(there was a url link here which no longer exists)

 

[Bertil]

Thank you all for all good advice!
Thus having a whole bottle of amidol I last night tried this formula:

Sodium sulfite 25g
Amidol 9g
Potassium bromide 0,5g
Benzotriazole 0,1g
Citric acid 0,7g
Water 1 liter
(roughly Cole Weston’s formula with some change in the anti-fog part)
I made some contact prints from a 8x10 negative on Fomatone MG 131; everything worked quite normal concerning exposure time and developing time, and the result quite nice but nothing special.
Now, I haven’t had time to make more comparisons with other papers and other developers. Perhaps no need to invent the wheel one more time, so perhaps reasonable to ask inventors still around!

1) What is the main virtue of amidol supposed to be? Edward and Cole Weston recommended and used amidol formulas; Wolfgang Moersch was recently quite happy being able to produce a stable amidol developer (Amidol plus, http://www.moersch-photochemie.de/co...sitiv/8/amidol).
+ Is it a developer particularly interesting for plain bromide papers?
+ Giving a warm tone on many different types of paper just using bromide (no bz)?
+ Papers available today for which amidol is of some special interest?

2) The amount of amidol that I have seen in various formulas seems to vary between 6-9g for 1 liter working solution. Edward’s formula 8g; Cole’s 9g; GAF 113 6,6g; Ilford ID-22 and ID-30 6g.
+ Is the amount mainly a question how many prints it will process, or does it make some change to the prints?
-- I used Cole’s 9g and I think (just a feeling) that I got a quite hard working developer, at least not soft working.
//Bertil

 

[Bertil]

I've now learned better to use APUG's (Google) search functions to find sites and threads to answer different questions!
I think the answer to my questiones above are something like:
+ the main virtue of amidol is that it can give a very deep black on many papers (often warm tone), thus not particularly interesting for just plain bromide papers.
+ Potassium bromide vs. BZ for image tone: experiment!
+ amount of amidol to 1 liter developer: probably more a qustion of how many prints/liter rather than other features of the print.
//Bertil

 

[Kirk Keyes]

What is the main virtue of amidol supposed to be?

It's magic! If you are brave enough to put your fingers in the solution, it will stain you fingernails black.



I'm not an amidol user, but my understanding is that it works well with water bath development, for lowering contrast when using fixed grade papers.

As I use VC papers, I control contrast with the paper, not the developer.

 

[Ian Grant]

Amidol is also a good word to use backwards

Ian

 

[Bertil]

Ok Lodima! I see. I've seen something about this Lodima Fine Art paper [http://www.michaelandpaula.com/mp/newpaper.html] but have no experience. Looks very interesting;
Thanks!
//Bertil