An Improved Process for the True Reproduction of the Colours of Nature in a Compound Photographic Print.
Year: 1888

page_text: Date of Application, 14th Sept., 1888
Complete Specification Left, 14th June, 1889-Accepted, 20th July, 1889
PROVISIONAL
SPECIFICATION.
An Improved Process for the True Reproduction of the Colours of
Nature in a Compound Photographic Print.
I HENRY CHARLES BOND, of Highland Road, Bromley in the County of Kent,
Schoolmaster, do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved process for the true reproduction of the
colours of nature in a compound photographic print and is as follows.
I take three plate glass troughs, composed of two thin sides cemented together
round the rims and held apart by narrow strips of plate glass of suitable thickness, and
fill these with liquids, each of such colour as shall transmit all solar rays, except those
forming one of the primary colours.
Thus The first will be filled with a green solution, (e.g. chlorophyll in alcohol)
which transmits all rays but red the second with an orange solution, (e.g. ferric
sulphocyanide), which transmits all but blue and the third with a purple or puce,
which transmits all but yellow (e.g. aniline puce dye), or the three slides with
such other liquids as shall be found to possess the properties.
:
The first of these colour screens is now hung by loops attached to its upper corners,
immediately inside the lens of a camera, and a colour sensitive gelatine dry plate
is exposed behind it, giving as a result a picture in which the red solar-rays have
had no effect at all.
With the second screen, a picture is obtained in which no blue rays take effect, and,
with the third, no yellow rays.
On developing these images, certain striking differences are noticeable between
each.
From these negatives, prints are next taken by contact, on paper coated with
bichromatised gelatine, or on glass coated in the same manner (collotype process); &
in the former case the image is transferred to the lithographic stone.
Each picture is now inked up, with a transparent and brilliant ink, complementary
in colour to the colour of the screen under which the negative was exposed.
Each colour is next printed in turn on to the same piece of paper, exactly as
in chromo-lithography, and the result is that the red ink takes those parts of the
picture where nothing shewed through the green screen, and no effect was produced
on the green plate; the blue ink takes the parts where the orange cut off the light,
and the yellow ink, those parts obliterated by the purple screen. The resulting point
if the colours of the colour screens, and of the inks have been exactly balanced, will
be found to pourtray all the colours of nature, as the secondary and tertiary
colours, and the deep tones of the shadows will be correctly given where the pure
primary tints overlap.
These coloured pictures may also be printed in gelatine tissue, stained to the
required colours after development with aniline or other dyes, and the three skins
superimposed, for the Magic Lantern Slides.
Dated this 14th day of September 1888.
HUGHES & SON,
5, Chancery Lane, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improved Process for the True Reproduction of the Colours of
Nature in a Compound Photographic Print.
I HENRY CHARLES BOND, of Highland Road, Bromley, Kent, Schoolmaster, do
hereby declare the nature of this invention and in what manner the same is to bo
[Price 40.1

page_text: performed, to be particularly described and ascertained in and by the following
statement:-
My Invention relates to an improved process for the true reproduction of the colours
of nature in a compound photographic print, and has for its object the obtaining of
the required results by natural means, without the use of the brush or any manual
application of pigments, such as Crystoleum, to the finished-prints. In carrying
my invention into practice, I take three plate glass troughs, composed of two thin
sides cemented together round the rims and held apart by narrow strips of plate glass
of: suitable thickness, and fill these with liquids, each of such colour as shall transmit
all solar rays, except those forming one of the primary colours.
Thus The first will be filled with a green solution, (preferably chlorophyll in
alcohol), which transmits all rays but red: the second with an orange solution
(preferably ferric sulphocyanide), which transmits all but blue; and the third I-fill
with a purple or puce (preferably aniline puce dye) which transmits all but yellow,
or I may
fill the three slides with such other liquids as shall be found to possess these
properties.
The first of these colour screens is now hung by loops attached to its upper
corners, immediately inside the lens of a camera, and a colour sensitive gelatine dry
plate is exposed behind it, giving as a result a picture in which the red solar-rays have
had no effect at all.
With the second screen, a picture is obtained in which no blue rays take effect,
and with the third, no yellow rays take effect. On developing these images, certain
striking differences are noticeable hetween each. From these negatives, prints are
next taken by contact, on paper coated with bichromatised gelatine, or on glass coated
in the same manner (collotype process), and in the former case the image is transferred
to the lithographic stone. Each picture is now inked up with rollers and lithographic
ink of a transparent and brilliant character, complementary in colour to the colour of
the screen under which the negative was exposed. Each colour is next printed
in turn on to the same piece of paper, exactly as in chromolithography, and the
result is, that the red ink takes those parts of the picture where nothing shewed
through the green screen, and no effect was produced on the green plate: the blue
ink takes the parts where the orange cut off the light, and the yellow ink those
parts obliterated by the purple screen. The resulting point, if the colours of the
colour screens, and of the inks have been exactly balanced, will be found to pourtray
all the colours of nature, as the secondary and tertiary colours, and the deep tones
of the shadows will be correctly given where the pure primary tints overlap. These
coloured pictures may also he printed in gelatine tissue, stained to the requisite colours
after development; with aniline or other dyes, and the three skins superimposed, for
Magic-lantern slides and the like.
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 :-
The process for obtaining the true reproductions of the colours of nature in a
compound photographic print, as hereinbefore described and for the purpose set
forth.
Dated this 1
_ 1000
HUGHES & SON,
5, Chancery Lane, London, W.C., Agents for the Applicant.