Heating chemicals

[Xícara de Café]

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Hello,

I recently got a copy of the 3rd edition of The Darkroom Cookbook by Steve Anchel. I'd like to make the direct selenium toner "Dassonville T-55" (Formula #162). The first step involves mixing the sodium sulfite in 100ml of warm water. The directions then say to add the selenium and "slowly heat" until dissolved. I'm uncertain how to do this. Can I simple dunk my beaker into a bath containing boiled water (off the heat) and stir until dissolved? Alternatively, can I place the beaker directly on a hotplate set to low and do the same, or should I set up some type of bain-marie and start heating from room temperature?

Yes, I've read all the safety information and will take all necessary precautions.

Thanks,

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[Xícara de Café]

Hmm. This post here says that the selenium in T55 needs boiling to dissolve into solution:

https://www.photrio.com/forum/threads/looking-for-the-kodak-selenium-toner-formula.96284/post-1278543

I have no fume hood at home but planned to do this outside.

[maxspbr]

Hi.

Do not put your Becker directly heating. You put it into hot water. The sulfite solution won’t boil, I think. 

[Xícara de Café]

Thanks @maxspbr. I ended up starting a discussion on this topic on the photrio forum here: https://www.photrio.com/forum/threads/time-to-dissolve-selenium.203553/#post-2751154

A great idea suggested there was to use sodium selenite instead of selenium as it is much more soluble in water and does not require 2 hours of boiling under a fume hood!

I see you're in São Paulo. The formula that uses sodium selenite also requires ammonium thiosulphate (tiossulfato de amônio). I can find this in pure form but it is super expensive. In solution it's meant to be a lot cheaper but I'm finding it hard to source.

Any idea where I might find ammonium thiosulphate in solution in Brazil? A company called Amonex in São Paulo has it but they've not responded to my enquiries and may not sell small quantities to individuals anyway.

All the best!

54 minutes ago, maxspbr said:

Hi.

Do not put your Becker directly heating. You put it into hot water. The sulfite solution won’t boil, I think. 

 

Edited January 3, 2024 by Xícara de Café

[maxspbr]

Surely you can get it from stores dealing with reagents for laboratories. It should not be so expensive.  
 

I made selenium toner a few times, and not your fórmula - I surely got mine from Jacobson’s or Del Conte’s formularies, my favorites. If you want I can show you.
 

 I like to compound my chemicals but the toner has a terrible smell and too much work, so went back to Ilford. 

[Xícara de Café]

On 1/3/2024 at 8:04 PM, maxspbr said:

Surely you can get it from stores dealing with reagents for laboratories. It should not be so expensive.  
 

I made selenium toner a few times, and not your fórmula - I surely got mine from Jacobson’s or Del Conte’s formularies, my favorites. If you want I can show you.
 

 I like to compound my chemicals but the toner has a terrible smell and too much work, so went back to Ilford. 

Hi Max,

Sorry for the tardy reply. I travelled mid-conversation! Yes, if you have some links, please send. Marinho in São Paulo has the Ilford Selenium toner at R$639. This is the best deal I've found and perhaps it would simpler just to buy this. From abroad, it's much more expensive. eg. B&H - with taxes and shipping is US$209 = R$1.031!

I've tried quite a few chemical suppliers in Brazil but haven't found one that sells ammonium thiosulfate. I like the idea of this chemical since I can use a soluble form of selenium to make the toner - so no boiling. Can be used in rapid fixer too.

All the best,