We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
Prismatic Dispersion and Allied Processes 669
is described, each color element being blocked out in turn. Subsequently*7 a total reflecting prism was placed behind the lens, and behind this a plane plate, and the interference of the two was said to obviate the use of color filters. The reflection device might be replaced by one having multiple layers of air, similar to that employed in the Lippmann interference spectrum. For making the cylinders for forming the lenticular elementary forms, the photogravure process was claimed,38 starch grains being used as the resist. An exhibition of this lenticular system, which has been called the K. D. B. (/Celler-Dorian, Berthon), was given in Paris" and was very highly spoken of.
Pathe Freres40 patented a method of projecting lenticular films, in which filters were arranged not in the lens, but between the condenser and the film, the lenticular surface of the latter facing the condenser. Three prismatic elements, which might have a divergent cylindrical curvature, might be affixed to the plane face of the condenser. In a later patent41 an improvement is disclosed, in which convergent cylindrical prismatic surfaces were used, which were adjustable. And a method is described of so adjusting them that each ray passed through its respective element. The use of lenticular surfaces42 for a two-color stereoscopic process is outlined. Complementary colors were to be used and the results viewed through suitable spectacles.
L. Landry43 patented a compromise between the purely prismatic and lenticular forms, as he suggested the splitting up of the light by means of prisms, with the use of a crimped support, as shown in Fig. 196. The prisms were staggered and immersed in a liquid, the mean refractive index of which was near that of the glass prisms, such as cinnamic ether. This has a very high dispersion, so that the yellowish-green rays JV had about the same co-efficient of refraction as the glass, whereas it differed considerably for the red and violet.
L. Tissier44 proposed to eliminate the use of filters also in this process by the use of spectral dispersion, which might be obtained by prisms, nonachromatic lenses, diffraction screens or multiple prisms etc In the case of the multiple prisms they are shown immersed in cinnamic ether. The use of a number of prisms, immersed in a liquid, was patented by Pathe Freres.45
M. Behrens48 patented a method of producing lenticular supports by using a plastic film, or one that could be made so, and impressing depressions in the same by means of small spheres. The interstices were to be covered with an opaque coating, and the depressions filled up with a medium, the refractive index of which was so chosen that they would act as positive or negative lenses of the desired focal length. Gaumont47 stated that when using K.D.B. films it was impossible to print by contact, as the elements formed a real diffraction grating. They, therefore, proposed to take separation negatives as usual, make three monochromes,