Re: Coating Box for Becquerel Development
Bruce, Your fuming box looks nice and should work, but if it's not relatively airtight, the iodine crystals will dissipate (and eventually disappear) faster than if the box was airtight. You will also smell the iodine whenever you enter the room of a non-airtight fuming box. Because the crystals tend to be hygroscopic, they will have a greater tendency to adsorb moisture from the air, eventually producing puddles of liquid in your box. And lastly, if you can prevent the atmosphere from escaping from your box when you slide your plate over the iodine crystals, you will have a much better chance of getting an evenly sensitized plate that has a relatively predictable sensitizing time. Make sure your iodine is sprinkled into a glass/pyrex dish. Don't put them directly on the wood bottom. A layer or two of cheesecloth laying directly on top of the crystals will help keep them from moving around, plus, it's supposed to even-out/equalize the intensity of the rising iodine fumes (a theory put forth in the 1850's which I'm not sure is actually valid). Here's a photo showing the 8" x 10"-format sensitizing boxes I built in 1998 (my mercury chamber is inside the fume hood in the background). http://www.pce.net/idag/Dag%20fuming%20boxes%20and%20mercury%20chamber2.JPG My boxes are a traditional fuming box design, and were modeled after the boxes built for Ken Nelson, who previously taught the daguerreotype workshops at the George Eastman House. The rear half of the sliding plate holder, sticking out from the center of the box, has a piece of ground glass attached to the bottom of it so that it can provide an airtight seal against the upper lip (also ground) of the glass dish the iodine crystals are sitting in. When the boxes are not being used, the handles on the very top of each box are turned clockwise in order to apply downward pressure on the sliding plate holder, which in turn pushes against the glass dish, providing an airtight seal between the dish and the sliding holder's glass underside. Newer fuming box designs have now eliminated the need for the long sliding plate holder, which is twice as long as the actual box. Good luck, Rob McElroy Contemporary daguerreotypist Buffalo, NY Bruce McCaughey wrote:
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