I was really inspired watching this video of Colombian photographer Camilo Sabogal making Becquerel Daguerreotypes on mirrored glass.
It solves the problem of making silver plates that had stopped me trying. There is only one hurdle remaining. Building a fume hood is not possible because my dark space is in the middle of the building. I was wondering how long the sensitised plates would last before exposure. If they were stable I could iodide fume them somewhere else. I presume the silver iodide is pretty stable in the dark.
Does anyone have any experience?
That's really cool, I hadn't seen he had been working with daguerreotypes.
I wrote a guide on ultra-low cost plates a while back.
I wasn't able to watch all of Camilo's video because I'm at work, but it looks like he's silvering his own plates. Back in the day I would buy old mirrors from thrift shops and remove the backing, exposing the silver. I found it advantageous because commercial coatings adhered to the glass much better than my self-coated ones did, tended to be thicker, and usually had a better shine pre-polish. The disadvantage is that you were taking a roll of the dice regarding silver thickness, and occasionally a backing that Citri-Strip couldn't remove.
Regarding your question about sensitized plates - daguerreotypes tend to start to fog pretty fast, even in the dark. IIRC it has to do with contact with oxygen. I sensitized this plate the morning of shooting, and developed it about 7 hours later. It looks good but even that was pushing it.
I think John Hurlock did some tests where he stored pre-sensitized plates in a vacuum chamber and was able to prolong their life at least for a few days.
Before I put in my fume hood, I used povidione iodine from the drug store to sensitize plates. It is much, much weaker than elemental iodine. It takes about 2 hours to get to a first cycle magenta, where in my fume box it takes about 2 minutes. Povidone iodine causes a sort of frostiness on the sensitized plate. I'm not sure what this is exactly, but it tends to go away after fixing anyway. I think it might eat through a bit more silver than elemental iodine, but I'm not totally sure.
