- Sensitive dry plates and
- Plate holders or shields,
- The Camera box,
- The view lens,
- The tripod or Camera stand,
- The instantaneous shutter,
- The focussing cloth, and a
- Carrying box to contain the whole.
It is necessary that the beginner should receive some instruction in the use of each of these articles, and for that purpose we will consider them in the order above given.
DRY PLATES.
The manufacture of dry plates has now reached such a state of perfection that the purchaser may procure them of every grade of sensitiveness, each of the several grades of a perfect uniformity and all of them very free from imperfections and blemishes. And also the prices have been so reduced of late that the incentive to manufacture on the part of individuals for their own use is almost entirely lacking. However, there may be found p145 a certain interest and fascination in preparing plates for one's own use, which would prompt some to incur the outlay and trouble incidental to such a course, and for those full instructions and formulæ may be found in the first part of this book.
It will, however, be found, after due trial, that for work of importance, and where certainty of results is desired, it will be better to procure the plates of some maker of established reputation, and of such a grade of sensitiveness as will be most suitable for the work in hand.
Certain makers of dry plates use the Sensitometer to ascertain the degree of rapidity of each and every emulsion produced in their works. The ascertained degree of rapidity is indicated on each box of plates by the Sensitometer number—the higher the number, the more sensitive the plate. The highest numbers attained up to this time are from 20 to 25, and these numbers would indicate a very high degree of sensitiveness, such as render plates of 23 to 25 quite suitable for work requiring the shortest possible, in fact, instantaneous, exposures, such as bodies in motion across the plane of focus. Views of still life are better made with plates of a lesser degree of rapidity.
The handling of dry plates of such extreme rapidity requires great care. The boxes should never be opened, even the outer wrappings should not be removed, except in the darkened room and by such a light as that produced by Carbutt's dry plate lantern or some similar device. When plates are taken from the boxes for the purpose of fitting the holders, they will be found to have one clear, smooth and shining surface. This is the back of the plate and is clear p146 glass; the other surface is of the same color, but of a mat or dead color, not reflecting so much light. This is the sensitive surface, and before being placed in the holder or shield it should be brushed with a soft, flat camel's hair blender, to remove any dust that may be attached to the surface. This brush should be used for no other purpose; and should be used without pressure, merely touching the surface of the plate. The plate may then be put in the plate carrier of the shield, with the sensitive surface outward, and when the carrier is run into its place in the holder, the sensitive surface is next the slide or door. It is of some importance that attention should be given to this manipulation, as it not unfrequently occurs that the wrong side of the plate is turned outward and the image, when the plate is exposed, is made through the glass and against the back of the film, and is reversed and thus rendered worthless, even should a good impression have been secured.
The holders or shields for dry plates for out-door work are always—except in the largest sizes—made double, each holder containing two plates.
