Thursday, May 5, 2011


Introduce a new Pyro-developer, which contains Menthol as Phenol.

Pyro-developer has been used in long history as much long as conventional developer. Recently Sandy King produced a several type of recipe, named Pyrocat X (X is substituted some alphabet).
Pyrocat has some character, higher image resolution with finer silver grain, higher image acutance and so on.
In detail refer to the text authored by Sandy King;

Mintol named my new pyro-developer is based on the Sandy King's Pyrocat.
Pyrocat used Catechol as a Phenol which gives complex with separated metal silver. Catechol is rather special chemical hard to purchase in my country Japan, and expensive.
Mintol contains Menthol as Phenol. Menthol is popular chemical easy to obtain at aroma shop. I alternated "FRISK" as Menthol crystal. FRISK is a well known mint tablet available at convenience store, highly contains Menthol. So I named it as Mintol.

Below is recipe tentative as I tried.

Metol                                          0.1g
Ascorbic acid                                0.3g
Sodium Carbonate (monohydrate)      3g
FRISK (trade name)                         5tablets

to dissolve in 600ml water at 20degree(C).
This solution have no shelf life, so you should use immediately after dissolving.

Example posted above used Tri-X at EI(exposure index)=400.
Agitate condition; continuously initial 30s, and 5s in every minute.
Total developing time is 14minutes at 20C.


ErikP said...

Ascorbic acid will work as a preservative, contrary to popular belief, metol will definitely last in solution, and unless mentol is very strange, this brew should have keeping properties....

Hovever as I understand thAT frisk is popular sweet mentol tablets (we have other brands here locally and I'm not familiar with this brand....) I'd like to note that the sweeteners are said to work like restrainers in a developer. This means the sweeteners reduces activity, which might be very very good, considering that methol and Acorbic acid both are agfgressively active substances...

This might mean that one does not need (as much) potasium bromide (KBr) to control chemical fogging levels....

Good luck, interesting piece of info!

PS seems they deleted your post over at photo net.....

yasu said...

Thanks for your comment, ErikP.
Ascorbate developer is general use for me too, and considering additional possibilities.
Photo net, i don't know what they said?

ErikP said...

I did put up a link on my blog, Ascorbate developers, over at
We're researching other alternatives, I welcome your addition to our common cause!