Improvements in and relating to Method of and Apparatus for the Production of Coloured Photographs.
Year: 1895

page_text: Date of Application, 30th May, 1895-Accepted, 21st Sept. 1895
COMPLETE SPECIFICATION.
Improvements in and relating to Method of and Apparatus for the
Production of Coloured Photographs.
A communication from abroad by MACFARLANE ANDERSON, of South Avenue,
North Port, in the County of Stevens and State of Washington, one of the
United States of America, Photographic Scientist.
1, PETER JENSEN, of No. 77 Chancery Lane, London, Chartered Patent Agent,
do hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:—
My invention relates to improvements in method of and apparatus for the
production of colored photographs, of which the following is a Specification.
In the drawings forming a part of this Specification,
Fig. 1 represents a perspective view of a photographic apparatus, showing
diagrammatically the arrangement of the different parts employed therein, the side
of the casing being removed.
91
Fig. 2 is a detail front view of the "color value screen and the "half-tone
screen," superposed one upon the other, the latter being partly broken away.
Fig. 3 is a detail view of the "color value screen.'
Fig. 4 is a similar view of the "half-tone screen."
"
To construct my apparatus, I take wire of aluminum, silver or other suitable
metal, either round, flat or of any other cross-section, and stretch it over or fasten
it to a light frame suitably made of metal. The wire is strung in parallel lines
and the spaces left between the adjacent wires are of a width equal to one-half of
the thickness of the wire itself. Au equivalent or modified construction may
consist of a glass plate, having ruled upon it opaque lines, these lines bearing the
same relation to the clear spaces between them as the wires to the clear spaces
above described with reference to the preferred form. This device I call my
"color value screen."
To produce negatives giving the true color values from any desired subject, I
use the screen in front of an ortho-chromatic sensitive plate or other suitable
sensitive surface. The first exposure may be made for the red values and the
second, say for the green. In making the second exposure, the wire or glass
screen, as the case may be, is moved across the face of the sensitive plate, so that
an amount of the sensitive film is impressed or exposed equal to that previously
acted upon for the red values, that part being protected from further light action
by the interposing lines or wires of the screen. The movement of the screen
across the film covers the exposed parts as the unexposed parts of the sensitive
surface are brought into view. The third exposure for the blue color values is
proceeded with in a similar manner, the screen moving across the sensitive film :
like distance as in the two previous exposures, and bringing the remaining
unexposed parts of the sensitive surface to the action of the blue rays, the opaque
lines or wires again protecting the parts previously exposed from further light
action. This movement of the screen I prefer should be secured by suitable,
accurate, mechanical devices.
Co-acting with the color value screen in the reproduction of the true color values
in each exposure, are suitable color filters, that is, colored plates of glass, which cut

page_text: off or absorb all rays except those particularly required to impress the sensitive
plate. The movement of the color value screen across the face of the sensitive
plate is, of course, made simultaneously with the change of the color filters.
Transparencies made from negatives obtained in this manner will give an exact
color rendering of subjects photographed when said transparencies are placed upon
paper ruled with alternate lines of the primary colors and registering with the
same. The use of color line-ruled double transfer paper involves a novel method
of producing color pictures to be viewed by reflection.
To apply this invention to the production of color value negatives in cameras
now in use with a roll of sensitive film, the screen is permanently held in front of
the sensitive film in a ruil holder or camera and said film is made to travel across
and behind the same, the degree of movement in each exposure being regulated by
any proper device.
To produce half-tone pictures, I place immediately in frout of the color value
screen a frame, having tightly stretched across it very fine wires which are parallel
to each other and so fine and close together that a stipple or half-tone effect will
be produced. The wires in this half-tone frame should lie at substantially right
angles to those in the color value screen, and the frame supporting them is
stationary.
Like reference numerals indicate like parts in the different views of the
drawings.
1 is a camera and 2 the lens thereof applied in the usual manner at one end of
the camera. 3 is the colored plate or filter, 4 the frame which supports the wires
of the color screen, and 5 the wires of the color screen. 6 is the frame which
supports the wires of the half-tone screen, and 7 the sensitive surface which, as
above stated, may be of coated glass or other material in sheet or roll form, a
celluloid film or any other suitable support for the sensitive surface. As above stated,
when paper or other material in the roll is used, the apparatus may be so arranged
that the film shall move behind the color value screen, which remains stationary,
instead of the color value screen moving in front of a fixed plate or other support
for the sensitive surface.
In Fig. 21 represent the color value screen with the half-tone screen partly
broken away superposed upon it, the proportions of the two parts being so arranged
as to show more clearly their construction. The spaces between the wires are
represented by the numeral 8 and the fine wires of the half-tone screen are
represented by 9.
If tour or more exposures be required to accomplish the desired results, or if a
fer than three be desired, the color value eren may be made in any other
desired proportion of wires to the spaces between them, or the opaque ones to
the clear spaces on the glass screen, according to which form of color screen is
employed. The lines may also run in any other direction that may be desired.
It will be observed that by my impr vement, such range of movement can be given
for the production of the different color valuts as may be desired. Consequently
I can get the full development of each color. This is of great importance because
the exposure for the complete production of certain colors is necessarily much
greater than that for other colors, for instance, red requires an exposure of from
50 to 100 times that required for blue, and this statement applies to the other
colors in different degrees.
It will be obvious to those who are familiar with this art that various
modifications may be made in the details of construction of my invention, and
to a certain extent, in its method of employment; that is to say, it is not essential
that the light obstructing devices upon my color value screen should be of
metal. Although I prefer aluminum or silver wire for the purpose, any other
material may be substituted.
The color value screen aud the half-tone screen may also, if desired, be made all
in one structure; in other words the same frame may support both sets of wires or

page_text: light obstructing devices, or they may in the first instance, be made in two parts
and then fastened together in any suitable manner. The color filters may also be
located in different places from those shown in Fig. 1 and, in fact, various other
modifications may be made without departing from the spirit of my invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is:
1. The herein described method of producing colored photographic negatives
consisting in successively exposing different portions of the sensitive surface to the
action of light, protecting parts previously exposed from the action of light, and
interposing between the lens and sensitive surface at each exposure a colored
filter of the color desired at such exposure.
2. The herein described method of producing colored photographic negatives
consisting in successively exposing different portions of the sensitive surface to the
action of light, protecting the parts previously exposed from the action of light,
continuously protecting the sensitive surface against the action of light in lines
transverse to the portions which are exposed, and interposing between the leus
and the sensitive surface, at each exposure, a colored filter of the color desired at
such exposure.
3. The herein described method of producing colored photographic negatives,
consisting in interposing between the lens and the sensitive surface a movable
device adapted to protect successively certain portions of the sensitive surface and
to expose successively certain other portions of the sensitive surface.
4. The herein described method of producing colored photographic negatives
consisting in permanently protecting certain portions of the sensitive surface
against the action of light and successively exposing different portions thereof.
5. The herein described method of producing colored photographic negatives
consisting in interposing between the lens and the sensitive surface, devices which
intercept the light rays from acting upon the sensitive surface and in moving the
sensitive surface behind such obstruction by successive minute movements.
6. The combination of a screen composed of a plurality of wires, bars or other
light obstructing devices for intercepting the passage of the light, means to move
said screen, a lens, a color filter and a sensitive surface in the rear of the screen.
7. The combination of a screen composed of a plurality of bars, wires or other
light of structing devices for intercepting the passage of the light, means to move
said screen, another screen of fine wires or other light obstructing devices, which
run trausversely of the light obstructing devices in the first named screen, a lens,
a color filter, and a sensitive surface.
8. The combination of a screen composed of a plurality of bars, wires or other
light obstructing devices for intercepting the passage of the light, a lens, a color
filter and a sensitive surface placed behind said screen.
9. The combination of a screen composed of a plurality of bars, wires or other
light obstructing devices for intercepting the passage of the light, means to move
such screen, a lens, a color filter and a sensitive surface.
10. The combination of a screen composed of a plurality of bars, wires or other
light obstructing devices for intercepting the passage of the light, another screen
of fine wire or the like running transversely to the bars or wires of the first
named screen, a lens, a color filter, a sensitive surface and means for moving the
sensitive surface.
11. The combination of a screen composed of a plurality of bars, wires or other
light obstructing devices adapted to intercept the passage of the light, separatel
from each other by a space less than the width of said bars or wires, a leas, a
color filter and a sensitive surface.
12. The combination of a screen composed of a plurality of bars, wires or other
light obstructing devices adapted to intercept the passage of the light, separated

page_text: from each other by a space less than the width of the bars or wires, and other
wires or like devices arranged transversely of the bars or wires of the first named
screen.
Dated this 30th day of 1905
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.