Potassium Iodide Instead of Potassium Bromide

[strangepics]

Hello PUGers.

I need to mix a developer, with the recipe calling for 1 gram Pot. bromide. I do not have Bromide. I have pot. iodide. If I were instead using iodide, how much iodide would I need? I understand I would need very little, but how much?

Thanks.

 

[Andrey Donchev]

Hi, according to Anchell's "The Darkroom Cookbook" sec. ed. 1/10 to 1/100. I have read, but I can't remember where, that when Bromide is substituted by Iodide the image tone gets cooler. I think that you can start with 1/50th and if the image is not too cool for your taste to rise the amount to 1/10th or to desired tone. I just ordered some Pot. Iodide to replace the Pot. Bromide because I found that on the particular paper I'm using right now (Adox Fine Print Vario FB / Efke Varicon) the Bromide gives an unpleasant warmish tone when dry. I tried first to use Benzotriazol instead of Bromide and the results where better, but if I can get even cooler images without using Amidol or some kind of toning (Gold, Iron) will be best!
Anyway, I wish you luck!

Andy

 

[Ian Grant]

You'd probably be better adding nothing rather than Potassium Iodide.

Ian

 

[Andrey Donchev]

Why Ian?

 

[dancqu]

You'd probably be better adding nothing rather
than Potassium Iodide. Ian

Although I've not kept exact records, testing
paper developers with no bromide included
has lead me to conclude that some papers
do not need a bromided developer. Also,
some may need more than others. Dan

 

[Photo Engineer]

Potassium Iodide can completely inhibit development by some paper emulsions. It is not a good idea to use it. When used in a film developer, it is usually used at the milligram level.

It is very very reactive and a powerful inhibitor. Take care if you do use it.

PE

 

[desertrat]

Although I've not kept exact records, testing
paper developers with no bromide included
has lead me to conclude that some papers
do not need a bromided developer. Also,
some may need more than others. Dan

I mix up D-72 from bulk chems without any bromide, and it seems to work fine with Ilford MG IV FB. I haven't noticed any fogging or contrast issues.

 

[strangepics]

Wait! I am sorry. I should have mentioned that this is for a film developer. In particular the Microphen-like developer:

Water(50C) - 750ml
Sodium Sulfite - 100g
Hydroquinone - 5g
Borax - 3g
Boric Acid - 3.5g
Potassium bromide - 1g
Phenidone - 0.2g
Water to make 1000ml

I mixed 4x this volume (with 4x the ingredients of course) with 20 ml of 0.001% of potassium iodide restrainer yesterday and tried a test roll. The film was developed for 6 minutes. Awful fog similar to stand development for one hour. Obviously not enough restrainer.

Thanks!

 

[Photo Engineer]

I mix up D-72 from bulk chems without any bromide, and it seems to work fine with Ilford MG IV FB. I haven't noticed any fogging or contrast issues.

It strongly depends on what paper you use.

PE

 

[Ian Grant]

Wait! I am sorry. I should have mentioned that this is for a film developer. In particular the Microphen-like developer:

Water(50C) - 750ml
Sodium Sulfite - 100g
Hydroquinone - 5g
Borax - 3g
Boric Acid - 3.5g
Potassium bromide - 1g
Phenidone - 0.2g
Water to make 1000ml

I mixed 4x this volume (with 4x the ingredients of course) with 20 ml of 0.001% of potassium iodide restrainer yesterday and tried a test roll. The film was developed for 6 minutes. Awful fog similar to stand development for one hour. Obviously not enough restrainer.

Thanks!

This is not a Microphen type developer.

It's a PQ derivative of ID-11/D76. The new edition of Anchells Cookbook will have the correction. ID-68 is the Microphen type developer. In 1954 Ilford published some suggested formulae for Phenidone developers, Phenidone had only been commercially available for about 18 months. There are at least 3 variations of this PQ - ID-11 type developer published, before the final re-formulation as ID-68.

You could add 20 to 30 gms Sodium Cloride per litre to the working soluton. This is similar to a recommendation Ilford made in a technical sheet P10 in 1965. This should give extremely fine grain, compared to ID-11/D76, with about a stop speed loss.

Ian