Disposing of cyanotyping water

August 18, 2023 7:47 AM

I want to let friends do some cyanotypes on papers I have already prepared and then let them develop them under water themselves. Easiest is if they just rinse them in their hotel sinks and then dry them, but perhaps that isn't quite okay? Should they all wash them in a common basin and I then take care of that water in some manner?

Not looking for feelings so much as "this chemical is hazardous or disallowed in this way for this reason" above and beyond the mandate that only pee and poo should go in the drain. Is it worse than washing paint splashes off my hands down the sink for example.

posted by Iteki to Science & Nature (6 answers total)

You should be able to locate (or may already have) the Safety Data Sheet for the specific product(s) you'll be using, which will be much more accurate than having people guess which chemicals you've got. Google turned up the SDSes for three different products on the first page alone, each with its own set of instructions. The common thread through all of them was that exposure to acids will release toxic gas, but I'm unsure if that still applies when you're talking about treated paper and not whatever chemical in its crystalline form.

If you're unable to locate an SDS, you should at least say what specific products you'll be using to prepare the cyanotypes.
posted by fedward at 8:07 AM on August 18, 2023

The wastewater agency in the municipality where you are doing this will probably have some guidance online about what to pour down the drain and what not to (and what you should do then).
Cyanotyping rinse-water is almost entirely water already and it is likely fine to dump.
The cyanotype solution itself? I’d start by fully reacting it and then dispose in landfill (prussian blue, the pigment that you’re making, is not toxic or reactive.)
posted by janell at 8:28 AM on August 18, 2023 [1 favorite]

Best answer: I just took a class in cyanotype with an artist who does a lot of it. We had basins for rinsing but she had us empty them out in the gutter outside. She also ate a piece of apple that fell into one of the (used) basins when we were chatting.
posted by lapis at 9:05 AM on August 18, 2023

I agree with janell - rinse water should be fine so your friends should be fine to rinse it. The solution will be the issue and that will depend on local disposal rules.
posted by Ashwagandha at 10:33 AM on August 18, 2023

Response by poster: Thanks! As an adult mefite I was aware of "ring the authorities" and "check the materials sheet" alternatives and was looking for "practical magic" as it were. That the solution is to diöute as to make little difference seems to be a cromulent answer as does the apple eating anecdote.
posted by Iteki at 4:02 PM on August 18, 2023

Please don't drain it into the gutter, regardless. Storm sewers aren't typically run through a treatment plant and usually drain directly into the nearest waterway, and even if the chemical isn't the worst thing you can put there it's still far more likely to be handled correctly via the sanitary sewer.
posted by Aleyn at 11:56 PM on August 18, 2023 [1 favorite]