IMPROVEMENTS IN STEREOSCOPES
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by Victor Julien Cassaignes at the
Office of the Commissioners of Patents, with his Petition, on the
14th November 1862.
I, VICTOR JULIEN CASSAIGNES, of Gavundun, Canton de Montflanguin, in
the Empire of France, do hereby declare the nature of the Invention for
"IMPROVEMENTS IN STEREOSCOPES," to be as follows:-
This Invention has for its object the giving to the foreground and background
of a stereoscopic picture, when viewed through the instrument, a natural and
pleasing gradation of tints. For this purpose I color the prisms or lenses of
the instrument at the lower parts, or those parts through which the foreground
of the picture is viewed with a tint suitable for the foreground, I prefer a
yellow or golden color; and the upper parts of the prisms or lenses, or those
parts through which the background and sky of the picture is viewed, I color
with a tint suitable for the back ground and sky; I prefer blue for these parts.
These colors in passing from the bottom to the top of the prisms or lenses
I shade off the one into the other, in a regular gradation of tints. It is not
essential to my Invention that both the bottoms and tops of the lenses should
be tinted; a very good, although not so perfect an effect may be obtained by
tinting either the tops or the bottoms only with suitable tint, leaving the
bottoms or tops, as the case may be, colorless. This arrangement will also
produce on the stereoscopic image two different tints, that is to say, that one
part of the image will preserve its own proper tint, whilst the other part will
take the color given to it. In place of applying the tints to the lenses, a

page_text: tinted glass may be interposed between the picture and the eye, either over
or under the prisms or lenses, the glass being, as already described, so colored
that the fore and the back ground of a picture viewed through the instrument
shall appear with appropriate and different tints. Or for glass tinted as
above described strips of stained glass may be substituted, a strip of glass of a
suitable tint for the foreground being placed over or under the lower part of
each prism or lens, and another strip of a suitable tint for the background
being placed over or under the upper part of each prism or lens, or several
strips of stained glass may be used so as to obtain a gradation of tints in
passing from the bottom to the top of the picture, or the stained glass may be
applied only to the lower part of the prisms or lenses, so that the foreground
of the picture may appear suitably tinted, whilst the background remains
colorless, or vice versa, the background may be made to appear tinted and
the foreground colorless. In these cases, although only one color is added,
two different tints are produced on the stereoscopic picture, as before
mentioned. In place of colored glasses, other transparent colored substances,
such as gelatine, collodion, gum, horn, and others, may be employed to produce
analagous effects to those of colored glass.
My Invention consists essentially in producing the coloration of the stereo
scopic image by means of a transparent colored surface interposed between
the picture and the eye of the observer in such a manner that this presents
two or a greater number of different tints. This improvement can be applied
to all sorts of stereoscopes; and I name chromo-stereoscopes all stereoscopes
provided with it.