Airships past and present, together with chapters on the use of balloons in connection with meteorology, photography and the carrier pigeon . FIG. 211. — Camera forthree-colour photogra-phy. L THE I-NTEKPBETATION OF PHOTOGEAPHS. 838 any accidental injury that might be caused by jolts or inside of the box is divided into three compartments, corre-sponding to the three lenses. The plate is 8J by 9% in., and issimilarly divided into three parts. The focal length of the lensis about V)] in., and works with an aperture of F/45. Threecarriers are provided for the filters, which are placed
Airships past and present, together with chapters on the use of balloons in connection with meteorology, photography and the carrier pigeon . FIG. 211. — Camera forthree-colour photogra-phy. L THE I-NTEKPBETATION OF PHOTOGEAPHS. 838 any accidental injury that might be caused by jolts or inside of the box is divided into three compartments, corre-sponding to the three lenses. The plate is 8J by 9% in., and issimilarly divided into three parts. The focal length of the lensis about V)] in., and works with an aperture of F/45. Threecarriers are provided for the filters, which are placed immediatelyin front of the plate. The camera has no focussing screen,seeing that it is adjusted once for all. A shutter of the slit typeis used, and at the back there are the usual double-backs. Thewhole of the manipulation is done from the outside, and thedouble-backs are fitted with rolling blinds. Isochromatic platesmust be used, and they must be sufficiently sensitive to red lightto take an exposure in a tenth of a second. The plates are pre-pared with ethyl red in the following manner. One ounce of. Fig. 212. Sliding screen carrier for three-colour photography. Miethes ethyl red (chinoline, chinaline, ethyl nitrate) is dissolvedin 500 fluid ounces of alcohol, and forms a stock solution whichmust be kept in the dark. One fluid ounce of the stock solutionis taken and mixed with 100 ounces of water. The plate isimmersed in this mixture for two minutes and then washed inflowing water for another 10 minutes in the dark room. It isthen dried in a draught in the hot oven for about twenty minutes,but not more than twenty-five minutes. The solution can be usedfor a large number of plates; probably it is better to take halfthe above amounts, which ought to be sufficient for six or eightplates. The plates should be packed front to back, in whichcase they can be kept for months. The proper relative exposures for the red, green, and bluemust be adjusted by means of suitable stops. T
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Keywords: ., bookcentury1900, bookdecade1900, bookpubl, booksubjectaeronautics
