Negative Holders Plates
From the outset of photography ways have been sort to lighten the load of the photographer. In a period when whole-plate size glass plates held in dark-slides were the norm their weight limited what could be carried on an excursion. It might be thought that the introduction of celluloid in sheet and roll form was the answer that would sweep away the use of glass. This was not the case however; the uptake of celluloid was by no means immediate and probably did not overtake the use of glass with the serious amateur until the mid 1900s, it did though encourage many more people to take-up photography. There were several reasons for this: early celluloid films had a reputation for cockling producing slightly uneven sharpness; their speed deteriorated more quickly than plates and curling during development was a problem. Early sheet film had a much thicker base than later, but even so, was usually held in thin metal sheaths necessary to maintain flatness and, if in some kind of changing box, prevent light passing through to the next film. The sheaths fitted into conventional dark-slides which, then, had still to be used in field and hand cameras. To reduce weight and space camera manufacturers devised alternative ways of carrying plates and film in cameras and in accessories to fit existing cameras. As a result the period from around 1890 to the mid 1900s produced a fascinating variety of systems for storing and changing plates and films.
Types of Fitting
Wet-plate period slides, on British cameras, typically had flat edges and dropped into a slot in the top of the camera. They had a wide flange at their top to prevent stray light entering the camera, the flange tended to project to the edge of the camera (fig. B5, B10). Smaller stereo cameras were often loaded from the side with the slide having ridges along their edges that fitted into rebates in the camera back, better light exclusion meant that the flange could be dispensed with (fig. B6). In either case the draw-slide was fitted with a raised wooden finger grip or a leather tab. By the late 1870s most stand cameras had rebates to take slides with ridges.
Typically, on early continental cameras the top of the slide fitted flush with the top of the camera and inside the side edges of the camera, ridges were more often fitted on the edge of the slide to hold it in place.