THE BASE AND COPYBOARD.
A suitable camera having been ob tained, it is essential to provide satisfac tory means of overcoming vibration, if there is any likelihood of its occurring. This may be accomplished by having a swing bed suspended from the roof, as shown by Fig. 900, or by having a cradle arranged for from both back and front, with the control of both motions at the back within reach of the operator. In some of the more expensive apparatus mechanical adjustments are even provided for raising or lowering the front, shifting the lens, copyboard, etc., all from the back of the camera. Figs. 896 to 899 illustrate typical designs of process cameras, and give a good idea of the solidity of construction necessary. The reproduction camera shown by Fig. 899 is well adapted for large work.
base on springs (Fig. 901). If, however, the studio is in a quiet place, a rigid stand resting on a floor of concrete will meet every requirement ; while even a wooden floor may serve if pads of rubber or felt are placed under the legs of the stand.
The easel should be perfectly level and true, and may either be fixed at the end of the base frame or slide to and from the camera. It is a good plan to cover it with a thin layer of cork to facilitate pinning up the copies, and it is recommended to paint it a dead black. A convenient form of stand for use with mirror or prism and a fairly short focus lens is shown by Fig. 902. In this, it will be seen, the easel slides up and down the front of the stand.
This is obviously useful for copying ninny things which would be awkward to fix on an upright easel, besides which a down ward lighting is found to be very satis factory. It will be noticed that a glass shelf and a reflector are provided for photographing transparencies, etc.