To produce microphotographs en masse, Dagron used a long wooden box that contained, at one end, a glass negative of the image to be reduced. At the other end was the reducing camera with up to twenty-five small lenses and the sensitized plate. When the end with the negative was held to a light source, the image was projected into the lenses and onto the sensitized glass plate to create multiple positive transparencies, each measuring about two millimeters square. Dagron employed the Taupenot dry collodion process, which used albumen to keep the plates sensitive after they had dried. The exposures took up to six times longer than wet collodion, but this mattered less in microphotography than it would for, say, a portrait. Dagron had also cleverly made the plateholder adjustable, so he could reproduce up to 450 microphotographs onto a single plate.