View Full Version : Pyro question

10-Feb-2019, 19:19
Forgive me for the questions about pyro - maybe the answers are there already but I didn't turn them up in a search - I know it will stain my skin, but does the chemistry stain things like bathtubs? And is it safe to wash down drain?
Last question : if i'm using premixed liquid developer - should I worry about the fumes much? Not for me, but for our pearl gray cockatiel which would not be in same room but in the house - they are sensitive to fumes.

Mark Sampson
10-Feb-2019, 20:49
Pyro developers will stain trays, but most developers will. Your hands, perhaps, but you should be using gloves with any developer. Edward and Brett Weston's famous stained fingernails came from amidol-based print developer. Pyro won't stain your porcelain-rinse afterward to be sure- and it's safe topper down the drain. As it oxidizes the chemicals break down into non-harmful compounds. I've used liquid-based pyro developers for 25 years- fumes are not a problem. The potential hazard is in ingesting the dry chemicals as dust.
I got most of this information from "The Book of Pyro" by Gordon Hutchings. I would refer to it for more accurate information... invaluable if you plan to use a pyrogallol-based developer.

10-Feb-2019, 21:27
I have more experience with catechol-based pyro formulas and I can assure you it will stain just about anything! Regardless of which type you use, wear gloves at all times. Fumes are not a problem when mixing a working solution from liquid stock.

Pere Casals
11-Feb-2019, 06:22
Also remember that safety is first.

If you process at home best bet is using the safest chem you can find, in a bathroom Xtol or Caffenol is not a major concern, but pyro chem has to be managed with a lot more care, any spill is not nice.

I'm (sadly) a true "expert" in bathroom processing (now with better resources), but what I concluded is that darkbathrooms are for safe chem.

If you have a sink like this:


then you have no problem, it easy to work with "complicate" chem, no spill on the ground. But in bathrooms better using safe things, you may obtain the same without problems.

Doremus Scudder
11-Feb-2019, 11:16
Pyro will stain things! Take a look at my darkroom sink if you don't believe it. That said, if you clean up quickly and keep the developer on the porcelain, you should have no problem. I used PMK for years in my Vienna "bathroom/darkroom" and never stained anything. I put down a plastic bag to cover the counters and towels over that. I tray processed sheet film on those counters and spilled a lot of PMK, but the towels/plastic protected the counters just fine. Rinse your towels in hot water and hang them to dry if you've spilled developer. They will stain, so use dedicated towels.

Don't worry about fumes, but don't go sniffing the Solution A bottle! It can be potent. Once mixed to working strength, fumes are minimal. Do worry about skin contact; wear gloves and rinse and inadvertent skin contact immediately. If you're staining your skin, you've had too much contact - stop it.

I wouldn't think that the fumes from another room would hurt your cockatiel, but ventilate to be sure. For me, the acetic acid in the stop bath smells more than the developer.



16-Feb-2019, 10:14
Thank you to everyone for the information! I'll give pyro a try in the bathroom and if I like it, I will figure out a better place to work with it long term.

Joe O'Hara
16-Feb-2019, 16:33
You can avoid the stinky acetic acid stop bath smell by using a 1.5% solution of citric acid instead. Cheaply obtainable in food grade from any retailer that sells canning supplies. Dump it into the pyro when you're done (if you do this in the dark, enjoy the moment of chemiluminescence) and you'll be well on the way to neutralizing it. Your cockatiel will thank you.

It's fine for printing, too, where larger quantities are typical.

And wear your blue gloves, like those above said.