I think a good case could be made that use of potassium cyanide as a fixer for wet plate/ambrotype/ferrotype is much more hazardous than use of mercury vapor to develop Daguerreotypes. However, if you're really, really concerned, there's always the Becquerel method, in which the exposed Dag plate is placed in a cabinet and exposed to dim red light for several days, then fixed when judged to be sufficiently developed. The plate is much slower when developed this way, and you don't see results for the best part of a week (compared to a half hour or so for mecury process), but there's no mercury in sight.Originally Posted by JG Motamedi
Fuming the plates seems no great big deal to me -- bromine has such a strong smell that you couldn't breathe enough of it to do harm without noticing it, and it's also strongly colored, so a concentration high enough to do great harm with a single breath is actually quite visible. The same is true of iodine, plus the vapor pressure is so low that you have to heat the crystals to get enough vapor to treat the plate. The greatest potential for an accident, IMO, is in preparing the bromine fuming mixture, and working under a properly vented hood makes this little if any more hazardous than refilling the cells in a car battery without removing the battery from the car.