Metol for Phenidone

Harold33 · Oct 3, 2014

It's often said that when substituting Phenidone for Metol, one should use 1/10 as much Phenidone as Metol.

Since I often use Crawley's FX-55, I wanted to try a Metol version of this excellent developer putting 1 gr. Metol instead of 0,1 gr. Phenidone. As a result, the film was seriously underdeveloped, barely printable.

Any explanation for that ? My guess is that superadditivity of phenidone-ascorbate is not (at all !) the same thing than superadditivity of metol-ascorbate.

wildbill · Oct 3, 2014

I've done this for paper developers with success, just not for film. Here are several threads which may helpthere was a url link here which no longer exists)

Gerald C Koch · Oct 3, 2014

No, both combinations are super-additive. The substitution ratio between metol and phenidone is not a hard and fast rule. The ratio depends on the type of developer. In addition each mole of metol contains half a mole of sulfuric acid. This probably threw the pH of the developer off. Even if you had been successful the resulting developer would no longer be FX-55 but something different. A developer is a carefully balanced mixture. You just can't go around changing things.

If you want a metol-ascorbate developer look at the DS-12 recipe on the digitaltruth website.

Rudeofus · Oct 5, 2014

Gerald C Koch said:
No, both combinations are super-additive. The substitution ratio between metol and phenidone is not a hard and fast rule. The ratio depends on the type of developer. In addition each mole of metol contains half a mole of sulfuric acid. This probably threw the pH of the developer off.

This is particularly true in the case of FX-55, which is a quite dilute developer: 2 g/l Carbonate, 0.15 g/l Bicarbonate, 2.5 g/l Sulfite, 1.2 g/l Bisulfite, 1.3 g/l Ascorbic Acid. While 0.1 g/l Phenidone won't do much to the pH, 1 g/l Metol most definitely will (see Jerry's posting), and this would nicely explain the lack of activity in Harold's brew.

el wacho · Oct 5, 2014

You can make a reference negative based on phenidone then make a metol based batch and increase the alkaline components until the times approach the phenidone based time. I did a similar thing with fx37 and acheived my desired results. Yes there was a loss in speed but it was very close to box speed with tmax100.
Ps I didn't try to get the exact same time as time as not a main parameter. The visual qualities were the guiding principle.

Harold33 · Oct 5, 2014

el wacho said:
You can make a reference negative based on phenidone then make a metol based batch and increase the alkaline components (...)

I understand you, but raising the carbonate (or decreasing the bisulfite) in such a sensitive mixture will produce something else than FX-55.
I only wanted to see if it was possible to keep the excellent image provided by F55 using metol instaed of phenidone. Now, I saw.

Gerald C Koch · Oct 5, 2014

el wacho said:
You can make a reference negative based on phenidone then make a metol based batch and increase the alkaline components until the times approach the phenidone based time. I did a similar thing with fx37 and acheived my desired results. Yes there was a loss in speed but it was very close to box speed with tmax100.
Ps I didn't try to get the exact same time as time as not a main parameter. The visual qualities were the guiding principle.

There is no easy solution to this problem since there are two variables. Even if we adjust the pH we still do not know the correct substitution ratio for the metol.

When you substitute metol for phenidone you also lose any speed increase that the phenidone provides. So while you could get a working developer it would not be the same as FX-55.

el wacho · Oct 6, 2014

Yes, there is no easy solution to this problem but a bit of testing will certainly bring you close you an answer. i would encourage anyone to rely on a little advice and alot of personal experience on these matters. i have never understood the bizarre mystification that goes on regarding the 'secret knowledge' of developer design. Crawley was no doubt a master in this field but exploring a metol-phenidone substitution is not beyond the reach of anyone willing to do the testing. what disappoints me more is that those that do have the knowledge and experience seem to discourage any sort of experimentation. not for me thanks.

Xmas · Oct 6, 2014

el wacho said:
Yes, there is no easy solution to this problem but a bit of testing will certainly bring you close you an answer. i would encourage anyone to rely on a little advice and alot of personal experience on these matters. i have never understood the bizarre mystification that goes on regarding the 'secret knowledge' of developer design. Crawley was no doubt a master in this field but exploring a metol-phenidone substitution is not beyond the reach of anyone willing to do the testing. what disappoints me more is that those that do have the knowledge and experience seem to discourage any sort of experimentation. not for me thanks.

No one tried to stop you?

But it is easier to try and understand the chemical process & all the early developers were trial and error.

Tis said D-76 was first more formal developer where an optimum metol hydroquinol ratio for super additivity was employed (at a low pH).

http://www.lostlabours.co.uk/photography/formulae/developers/devD76_variants.htm

Then the sulphite was reduced, & people write books about it to help you...

Lots of information available to start you on slippery slope of a home brew.

Lots of people already tried to improve D76 so you are not alone.

Gerald C Koch · Oct 6, 2014

el wacho said:
Yes, there is no easy solution to this problem but a bit of testing will certainly bring you close you an answer. i would encourage anyone to rely on a little advice and alot of personal experience on these matters. i have never understood the bizarre mystification that goes on regarding the 'secret knowledge' of developer design. Crawley was no doubt a master in this field but exploring a metol-phenidone substitution is not beyond the reach of anyone willing to do the testing. what disappoints me more is that those that do have the knowledge and experience seem to discourage any sort of experimentation. not for me thanks.

There is no bizarre mystification or secret knowledge. The information is there for anyone willing to spend the time reading the applicable books. Read Mason and Glafkides and best of all Haist several times. Then purchase a good pH meter and a step wedge. THEN you will be prepared to tackle such a problem.

What people have been discouraging is the notion that changing FX-55 to something else is a worthwhile task. As I pointed out you lose any speed increase that you would get with FX-55. For an analogy it is like buying a new muscle car and then putting a 30 year old engine in it. You can do it but for what reason?

el wacho · Oct 6, 2014

to Mr Koch, thanks for an intelligent answer.

to Xmas, interesting answer. i'm still trying to understand the relevancy.

i do wish though that someone like Mr Koch would write an article about a practical approach to the matter. one can only hope.

Xmas · Oct 6, 2014

el wacho said:
to Mr Koch, thanks for an intelligent answer.

to Xmas, interesting answer. i'm still trying to understand the relevancy.

i do wish though that someone like Mr Koch would write an article about a practical approach to the matter. one can only hope.

A long list of manufacturers 'hacked' Kodaks D76 so you should not feel bad.

Ilford did a near clone ID11 and a modern version Microphen.

There are threads about other people's experiments if you search.

If you ask questions people will try to help.

el wacho · Oct 6, 2014

To Xmas,
You seem to think that i need d76 and that i shouldn't feel bad about something. I addressed the op. Could you clarify please because the original issue has always been about the metol - phenidone substitution and you're going on about d76. There is a confusion but it most certainly does not reside within me!

Metol for Phenidone

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