Plate Changing Chamber
DESCRIPTION AND DIRECTIONS FOR USE.
No matter what process we employ to retain the sensitiveness of our plates, it is most objectionable that the glasses should be made to slide by their gravity from the plate-box to the slide; for if we employ either honey, glycerine, or oxymel as preservative agents, the chances are considerably in favor of an amount of dust settling on the surface, the dust being in a great part formed by the attrition of the roughened edges of the plate against the plate-box. Another inconvenience attending the use of a box when the plate has to slide, is the danger that exists under that arrangement of ripping the film from the edges of the plate by the friction against the groove in the box which holds it. These may appear very trivial matters, but they are nevertheless great drawbacks to successful operations.
We may mention that the plan we are about to describe is equally applicable to all Cameras of moderate size. We will, however, take our description from the form of apparatus adapted to a double lens Stereoscopic Camera.
The Camera (A) is furnished at its back with two wires (B). On these wires slides the plate-box (C), which has previously been fitted at its sides with two sockets (D). Just inside the back of the Camera box is a spring (E), and on the top of the Camera is a button (F), which secures the dark slide in its place.
We now slide the box of prepared plates (C) on to the wires (B), the lid of the box opening from the Camera; wethen stretch over the whole affair, the black light proof covering (G); this completes the arrangement, and now for the mode of operating.
The opaque covering is furnished at its side with two elastic rings. Into these thrust the hands, so that the rings may firmly encompass the wrist. Then open the plate-box, and throw the lid quite back. Next unbutton the door of the dark slide, and raise it until the spring (E) flies underneath it, and retains it in a horizontal position. This we will presume to be done with the right hand; the left hand being engaged as soon as the door is opened, in holding the plate that is already in the back in its place. The right hand being now at liberty, comes to the assistance of the left, and the plate that has undergone exposure is safely transferred to the vacant groove in the plate-box. This accomplished, the next plate is to be placed in the back, and the same operations gone through in the inverse order, the left holding the plate in its place, while the right releases the door from the influence of the spring (E), and re-buttons it, leaving the plate quite safe in the dark slide.
When we require to focus for a fresh picture, it is only necessary to remove the dark covering from that part of the Camera where the ground glass is placed. The picture can be seen without removing the plate-box or the whole of the covering.
It is obvious that there is no limit to the number of glasses that can be taken to the field of operations. In this way, several boxes holding a dozen each, can be strapped together and placed on the Camera, one by one, as occasion or opportunity may direct.
H. Silverlock, Printer, Doctors' Commons.
PRACTICAL PHOTOGRAPHY,
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Transcriber NoteMinor typos corrected. Images moved to prevent splitting paragraphs.
Transcriber Note
Minor typos corrected. Images moved to prevent splitting paragraphs.