What is causing this ammoniac smell?

[Ron789]

Sometimes when working in the darkroom, while printing but more often when cleaning up after a printing session, I get an ammoniac smell. I suppose it must be caused by chemicals getting mixed. Does anyone know what is causing this?

 

[Sirius Glass]

Do you have a cat that uses the darkroom to relieve itself?

 

[RobC]

or a horse. Have you been using a stable as a darkroom?

 

[RobC]

Fixer may have AMMONIUM THIOSULPHATE in it so that is the probable source. Hypam uses it and lots of others I think. Good ventilation is always recommended for darkroom.
Also always a good idea to read the MSDS sheets for the chemicals you are using so you at least have a clue about what they have in them.

 

[jimjm]

Some type of ventilation should help prevent this. Fixer is usually the least-pleasant smell, especially if you're using a lower dilution like 1:4.

I also run the tap while I'm pouring used chemicals down the drain, to dilute them more and ensure everything gets flushed thru the pipes. If you're not running the water and just dumping all your used chemicals down the drain, they may be mixing in the pipes and causing that ammonia smell. I read somewhere that repurposing used developer (alkali), stop bath (acid) and fixer actually makes a pretty good fertilizer. I've no first-hand experience with this, so don't blame me if it kills your prize-winning roses.

 

[ValoPeikko]

Ilford Rapid Fixer also has a nice ammonium smell I actually kind of like it. Makes me feel like I'm back in my fathers darkroom...

 

[piu58]

The fixer smells of ammoniac if you have displaced quite a lot developer into it. The capacity of the acid component (normally potassium metabisulfite) has been exhausted. You may add stop bath to the fuxer if you stiil want to use it.

 

[Ron789]

Thank you all for your responses!
I have a cat but don't let her into the darkroom.... might be cosy but not practical.
A horse and stable? My daughter would love that, but a stable on the 2nd floor seems a bit impractical to me.
Mixing developer and fixer is probably the cause.... I use stop bath and neutral fixer. When cleaning equipement some remainders may get mixed; I retain used developer and fixer in containers for disposal as chemical waste but the trays may have some residues that get mixed when cleaning them. Test strips may be the other cause: i use FB paper and put test strips in stop bath and fixer only for a short time; so the test strip may still contain developer by the time it goes in and comes out of the fixer.
Ventilation is indeed the answer; I have a good ventilator built in a wall of the darkroom but did not always switch it on as it is a bit noisy, disturbing the serene quietness in the darkroom that I like so much.... but I guess it's better to always switch it on.

 

[jamespierce]

As amusing as this thread is the answer is simple - You are mixing developer with fixer as you clean up which makes a terrible ammonia smell.. Perhaps in the drain...