View Full Version : Hydronal

2-Jan-2008, 22:59
Ok there isn't a developer called Hydronal but recently I began tinkering with my chemistry set and came up with this.

Usual disclaimers apply. You are responsible for your health and safety when making darkroom chemistry from scratch. If you have no experience with very caustic chemicals do a lot of research on the dangers as they are very real.

Pat Gainer on APUG put together a Concentrated Metol / Rodinal substitute that I made and have used over the past 12months. His formula is on APUG.

This is one I made the other night which seems to work quite well based loosely on his methodology.


You must wear gloves and eye protection and work in a well ventilated area -- this developer uses Potassium Hydroxide.

Water 60 ml at no more than 20c [68F]

Metol 2.5 gms
Sodium Sulphite 10.0 gms
Hydroquinone 5.0 gms
Sodium Metabisulphite 1.0 gm
Potassium Hydroxide 6.0 gms

Add water to make 100 mls

[1] Cool water at no more than 20c to mix the chemistry
[2] Add a small pinch of Sodium Sulphite to the water and then dissolve the Metol.
[3] Slowly add the Sodium Sulphite stirring constantly. A reaction will take place where the solution becomes white and opaque.
[4] Add the Hydroquinone and stir well for at least 30 secs.
[5] Add the Sodium Metabisulphite and stir well for at least 30 secs.


Potassium Hydroxide creates heat when added to water so it is a good idea to put your mixing vessel in a bowl of ice cubes to carry out the next step. And wear gloves and eye protection.


[6] Very slowly start adding the Potassium Hydroxide while stirring constantly. When you have added about half of the Potassium Hydroxide the white opaque liquid will start to clear back to a more transparent liquid. Finish slowly adding the Potassium Hydroxide.

[7] Top up the liquid to 100ml. Decant the developer to a small glass bottle.

I have only tried the developer with Arista Edu Ultra [Foma 200] but the results were very good.

Rate at 80 iso

1:150 @ 21c for 7 minutes 30 seconds

BTZS tubes, but I have found the times for a Jobo sytem are very close.

At the working solution of 1:150 the pH is 10.3

Based on comparative tests with Foma and D76 this developer appears to give similar film speed. Grain is tight and fine and the base fog is the same as the film processed in D76 @1:3.

This is only a guess but 1:60 @ 21c for Efke 100 rated at 50 iso for 7 minutes may be a good starting point. It is only a guess.

I have no idea if the developer has a shelf life - time will tell - hence the small quantity.