Roger Cole
Subscriber
Roger - I can't pin down the irritant in RA4. It's nothing corrossive like Ciba bleach, so doesn't give itself away by odor. I know a number of lab owners and their employees who got sensitized to RA4
and couldn't be around it. I can work with it for about a week and then all of a sudden only tiny
amts of the odor will irritate my resp system and make me very susceptible to cold virus etc. So I
opt just to do the actual chem mixing and dev outdoors during mild weather (to keep temp variables
within tolerance inside the drum). But ventilation is important even with much milder b&w chem.
My darkroom in TN was pretty well ventilated. Here and now - eh, well, I hung black plastic around the area of the basement I use and over the ceiling joists, mostly to prevent too much movement of too much dust into it from outside and dust falling from the ceiling, but it also cuts down on any light that leaks in from the blacked out windows and I can print in the daytime, or even with the stairwell light on at the other end of the basement. It can't be very air restrictive - I notice no problems with black and white. I do use brown toner outside that area, though, both for the smell and for the fact the fumes can fog paper or so I seem to recall reading.
The RA4AT stuff was, I think, more concentrated than regular RA4. Working with it for a couple of hours even in good ventilation would give me a sore throat for a day or two. After the change of stop and change to the printpod it wasn't too bad.