AN IMPROVEMENT IN PHOTOGRAPHY AND APPARATUS USED THEREIN
Year: 1876

page_text: LETTERS PATENT to Henry Vander Weyde, of Kensington, in the County
of Middlesex, for the Invention of "AN IMPROVEMENT IN PHOTOGRAPHY AND
APPARATUS USED THEREIN."
Sealed the 21st October 1876, and dated the 25th April 1876.
PROVISIONAL SPECIFICATION left by the said Henry Vander Weyde at
the Office of the Commissioners of Patents on the 25th April 1876.
HENRY VANDER WEYDE, of Kensington, in the County of Middlesex.
IMPROVEMENT IN PHOTOGRAPHY AND APPARATUS USED THEREIN."
"AN
My Invention consists in the application and employment in photography of a
leus of large dimensions constructed as hereafter described, and placed between the
source of light and the sitter or object to be photographed for the purpose of
concentrating the light or causing the rays of light to converge upon the sitter or
object, and to increase the illumination of the latter when the ordinary illumination
by daylight or other source is insufficient. For the purposes of my Invention I
prefer to employ a water lens, plano convex in form, and which may be constructed
of two sheets or discs of colorless or slightly tinted glass, of which one is bent or
of the proper spherical form, and the two fitted together in a suitable. frame, and -
the intervening space filled with water or other transparent colorless (or slightly
tinted) liquid.
Instead of being constructed of two discs of glass set in a circular frame the
discs may be composed of segments fixed in segmental frames, or the lens may be
constructed of a number of separate glass vessels, each of segmental form, so that
when fitted together a lens of the desired form is obtained, or the lens may be of
solid glass.
My Invention also consists in the combination with the lens above described of
a second lens for making parallel the rays of light collected by the first lens, and
my Invention further consists in the combination with the aforesaid lens or lenses.
of a mirror or other reflecting surface upon which the light, whether natural or
artificial, first falls, and is thence reflected on to the lens.
In using artificial light the lens and the mirror or other reflecting surface would
be parallel, and the source of light would be placed between them with a screen to
prevent the light falling upon the lens except from the mirror.

page_text: -
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Henry Vander Weyde in the Great Seal Patent Office on the 25th
October 1876.
HENRY VANDER WEYDE, of Kensington, in the County of Middlesex.
IMPROVEMENT IN PHOTOGRAPHY AND APPARATUS USED THEREIN."
"AN
It is well known that portrait photography depends for the artistic excellence of
its results mainly upon the power, breadth, and direction of the light by which the
sitter is illuminated. It has been found by practice that the hardest and least
suitable light for the purposes of portrait photography is light coming from a point,
such as artificial light or direct sunlight or daylight coming through a sinall
window, as the shadows in all these cases are hard and sharply defined. It is also
found that ordinary daylight coming through a broad window or skylight, as used
at present by photographers, produces softer effects, while very broad white sunlit
clouds throw a light possessing superior actinic power and softness combined.
The object of my Invention is to enable the same results to be attained with a
dull grey, red, or blue sky as with broad white sunlit clouds, and I attain this end
by rendering the daylight both stronger and softer, as hereafter described.
The Invention is also applicable for rendering artificial light artistically desirable
for the purpose of portrait photography. For this purpose I provide within the
photographer's studio or room in which the photograph is to be taken a large lens
placed between the source of light and the object or sitter to be photographed.
The lens I prefer to employ is a Fresnel annular lens of about five feet diameter,
such as is used in revolving lighthouses, but other kinds of lenses might be used, -
such as a water lens, variously constructed. In any case the form of the lens must
be such as to render convergent the rays of light entering through the window,
skylight, or other opening opposite which the lens is placed or reflected from a
mirror or other reflecting surface illuminated by daylight or artificial light, and
used in combination with the lens. The effect of these converging rays falling
upon a person placed within their focus is twofold, viz., a great increase in the
whiteness or actinic power of the light by reason of the rays being concentrated
towards a focus, and greater softness in the effects produced by reason of the light
falling at varying angles upon and thus embracing, so to speak, the sitter. This
soft and brilliant light composed of converging rays has never before been used for
the purposes of photography.
The light being condensed or concentrated as above described, the great :
objections (i.e., hardness and want of actinic power owing to the divergence of
the rays) to artificial light, such as the electric or magnesian light for photographic
purposes, are. obviated by my Invention, the result being more delicate and softer
modelling and shorter exposure. Artificial light thus becomes henceforth a
practical and desirable means of illumination in portrait photography.
In order that my Invention may be more readily understood, I will proceed to
describe it with reference to the accompanying Drawing, in which I have shown
diagram views of the Invention applied in different ways.
4
Figure 1 represents the interior of a room or photographic studio. A is the
annular Fresnel lens mounted to swing on gudgeons in a convenient portable frame.
This condensing lens is placed opposite the window or skylight B, so that the light
entering thereat will fall on the lens as represented by the parallel rays C, which
on passing through the lens A are refracted and caused to converge, as at D, towards
a common focus, between which and the lens the sitter is placed, as shown; E re-
presents the annular space surrounding the cone of rays D, which has been deprived 5
of the light which has been refracted towards the focus.
The form of the lens which I prefer to use will be seen by reference to Figure 2,
which shows a cross section of an ordinary annular plano-convex Fresnel lens.
Such lenses may be conveniently made for the purposes of my Invention by casting
the glass in moulds, and afterwards submitting the angular surface to the direct 5

page_text: action of a furnace until the surface runs and becomes smooth and glossy, thereby
avoiding the expensive operations of grinding and polishing except upon the plane
side. Each annulus or ring of which the lens is composed may be cast in segments
and joined together.
Figure 2 represents a studio ou the ground floor or basement. A is a lens as
before, and F a reflector placed at such an angle as to reflect the vertical rays from
the sky through the window B on to the lens A, by which they are concentrated
towards a focus as before.
Figure 3 represents an arrangement for applying artificial light. A is the lens,
and G is a paraboloidal reflector, in the focus H of which the source of light is
placed. The light used may be the ordinary electric or magnesian light sometimes
used in photography. The reflector G may. be made of sheet metal, silvered on the
internal surface. The divergent rays from the light at H are reflected in a parallel
direction on to the lens A, by which they are made to converge as before. A sheet
of tissue paper, or ground glass, or similar inmedium, might sometimes be advan-
tageously introduced between the source of light and the lens for the purpose of
softening the light.
Having described the nature of the said Invention and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein-before in part recited Letters Patent is,―
1stly. The application and employment in portrait photography of a lens, as
described, for concentrating the light by which the sitter is illuminated during
exposure, as and for the purpose herein set forth.
2ndly. The employment in combination of a lens and reflector, substantially
as described, for concentrating the light, whether natural or artificial, by which the
sitter is illuminated in the process of photography, as set forth.
In witness whereof, I, the said Henry Vander Weyde, have hereunto set
my hand and seal, this Twenty-fifth day of October, in the year of our
Lord One thousand eight hundred and seventy-six.
HENRY VANDER WEYDE. (L.S.)