View Full Version : Precautions when mixing and using Pyrocat-HD

G Benaim
26-Jul-2007, 01:55
Hi All,

In my 8x10 adventure I've decided to try pcat-HD, and order some from PF. Since I'm overseas I thought I'd save on shipping by getting the dry mix, but then started panicking when I read some threads on its toxicuty. So I read Sandy King's artilce and saw he reccomends just mixing it outside as a precaution. I'm curious what users of pcat who mix from dry chems are doing and what are you basing your decisions on. Also, when using it in darkroom, is ventilation essential, or are gloves enough? IOW, does the catechin release anything in dissolved form that can be harmful? Thanks in advance,


Ron Marshall
26-Jul-2007, 10:16
I wear gloves and eye protection when diluting the concentrate.

Apparently a small amount of toxic gas is evolved when the dry components are dissolved; which is why outdoors or a fume hood is necessary.

The premixed in glycol is easy and keeps very well.

Dan Schmidt
26-Jul-2007, 10:58
Basically from what I understand the dry form is the problem.

One nice thing is that you can get Pyrocatechin into solution very quickly with the PF kit since you don't have to weigh it out. Just cut the corner of the bag and shake the contents into your A bottle.

I use the PF kits and work in a big tray so that i can easily clean up spills. As long as you are not doing this in a closet sized room, things should be fine.

26-Jul-2007, 11:33
I've used the dry form of catechol, and you do have to be careful with it. First issue is, do not mix this stuff in a closed area - catechol evaporates, and the fumes are almost certainly not good for you. I mix mine in the garage, with the door open. Once the stuff is in solution, you don't have to worry about fumes so much - even less so when it's diluted for development.

I don't worry about getting any on my hands, since I just rinse it off right away. It's also very, very dilute when mixed up (1+1+100, to 2+2+100 for some alt processes, perhaps even slightly stronger). Gloves are probably not a bad idea, however, since you can absorb catechol through the skin.

Jeremy Moore
26-Jul-2007, 12:23
You can also order it in "dry pack" form from Bostick & Sullivan (http://www.bostick-sullivan.com). Call and check, but the last time I ordered I received the dry chemicals in opaque plastic bottles and all I had to do was add distilled water & shake. In terms of mixing this is probably the easiest and safest, though more expensive than buying the individual chemicals in bulk and mixing them up yourself.