AN IMPROVED APPARATUS FOR VIEWING PHOTOGRAPHIC PICTURES, AND THE PREPARATION OF PHOTOGRAPHIC PICTURES TO BE USED IN SUCH APPARATUS
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by Joseph Ponti, at the Office of
the Commissioners of Patents, with his Petition, on the 10th July
1862. A communication from abroad by Carlo Ponti, residing at
Venice, in the Empire of Austria, Optician.
I, JOSEPH PONTI, of Venice, in the Empire of Austria, but now residing at
No. 112, New Bond Street, in the County of Middlesex, do hereby declare
the nature of the said Invention for "AN IMPROVED APPARATUS FOR VIEWING
PHOTOGRAPHIC PICTURES, AND THE PREPARATION OF PHOTOGRAPHIC PICTURES TO BE
USED IN SUCH APPARATUS," to be as follows:-
This Invention consists in constructing an apparatus for viewing photo-
graphic pictures, resembling generally in form that of a "stereoscope," but of
considerably larger dimensions, and provided with only one large magnifying
lens, and only one representation of the picture (which is also of considerably
larger dimensions than those employed in "stereoscopes,") the object of
the Invention being to present readily to both eyes of the observer, without the
inconvenience of looking through two separate lenses, a representation of the
picture magnified to such an extent, and at the same time having the stereo-
scopic effect sufficiently to impart to the same the appearance of the object itself
in its natural size. The lens of this apparatus is, by preference, made of such
a size as to take in conveniently the sight from both eyes of a person, and a
shade surrounding the lens is made to project from the same towards the
observer, to prevent the eyes taking in any other rays of light than those

page_text: '
passing through the lens; this is also so arranged with adjusting screws, that it
can be brought nearer to or moved farther from the eyes, according as the
difference of sight requires it,
This apparatus is arranged in a horizontal position on a suitable stand, the
picture being in a vertical position, and the end of the apparatus where the
pictures are inserted being, by preference, made of an oblong form, provision
being made for causing it to revolve round a horizontal axis to such an extent,
that in one position the larger dimensions of the picture is horizontal, whilst in
the other direction it is vertical, so as to suit pictures of different proportions.
The apparatus is arranged for viewing either transparent pictures or pictures
requiring a reflected light, for which purpose it is constructed in the following
manner: A portion of the top and side of the apparatus, near the end where
the pictures are inserted, are made to open on hinges, and are provided on
their inner surface with reflecting mirrors in such a manner as to reflect the
light (which may be either artificial or natural, and is, by preference, situated
behind the end surface of the apparatus) more or less on to the picture,
according as they are adjusted in position. The light is then reflected from
the picture through the lens to the eye of the observer. For transparent
pictures the two before-mentioned reflectors are closed, and the end opaque
surface of the apparatus (which is also provided with hinges) is let down, so
that the light passes through the picture. The frame for holding the pictures
at the end of the apparatus is, by preference, made curved in such a manner
as to cause the picture to be slightly concave when inserted, to suit the form
of the lens. In order to prevent the bright light (particularly when it is
artificial and situated at the back of the apparatus) from blinding the eyes
when one picture is removed for the purpose of inserting another, a more or
less opaque flap is provided close behind the lens, which, by means of an
external lever, is instantaneously raised in front of the lens when the pictures
are being changed.
Another part of this Invention consists in preparing photographic pictures
to be employed in this apparatus in such a manner that they shall be capable
of representing consecutively both a day and night appearance of the object.
For this purpose the photographic picture is made on paper, or other suitable
material, that will both reflect the light and yet be transparent to a certain
extent, and is provided at the back with a sheet of transparent paper, or other
suitable material, that is coloured with transparent tints representing the effect
of night, moonlight, or artificial light, in a manner corresponding to the objects
on the picture. By this arrangement, if such pictures are inserted in the
before-described apparatus, the back of the same being closed and the two

page_text: reflectors opened, the light will be reflected on to and from the surface of the
picture, as before described, and a daylight effect will be produced; whilst, if
the two reflectors are then closed, and the back of the instrument opened, the
light will pass through the tinted back and through the picture itself, and the
night effect will thus be produced.