IMPROVEMENTS IN PHOTOGRAPHY BY PROCESSES WHICH COMBINE PRINTING, PAINTING, & TRANSFERRING, FOR THE PRODUCTION OF CROMO-PHOTOGRAPHS
Year: 1870

page_text: LETTERS PATENT to William McCraw, Photographer, 9, West Catherine
Place, Edinburgh, for the Invention of "IMPROVEMENTS IN PHOTOGRAPHY
BY PROCESSES WHICH COMBINE PRINTING, PAINTING, & TRANSFERRING, FOR
THE PRODUCTION OF CROMO-PHOTOGRAPHS."
Sealed the 10th June 1870, and dated the 31st March 1870.
PROVISIONAL SPECIFICATION left by the said William McCraw at the
Office of the Commissioners of Patents, with his Petition, on the
31st March 1870.
I, WILLIAM MCCRAW, Photographer, 9, West Catherine Place,
Edinburgh, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PHOTOGRAPHY BY PROCESSES WHICH COMBINE PRINTING,
PAINTING, & TRANSFERRING, FOR THE PRODUCTION OF CHROMO-PHOTOGRAPHS," to be
as follows:
This Invention relates to the production of chromo-photographs by
the combined processes printing, colouring, and transferring, in other
words to the making of pictures combining the fidelity of the photo-
graph with the character, quality, and appearance of an artistic painting

page_text: in oil colours, and that with the facilities of production of ordinary
photography.
In carrying out my Invention I do not use ordinary paper photographs,
but employ ordinary negatives for the production of prints or positives
on glass. For this purpose I coat one side of the glass plate with photo-
graphic collodion or other substance, which forms a structureless or
transparent film; this film, which contains the picture in light and
shade, I paint with its appropriate local colours; I now glue or cement
this painted surface to canvas or other final support; the glass having
less adhesion to the film than the cemented surface has to the canvas is
easily removed, leaving an untouched photographic supported by colours
transferred to canvas. The picture is now complete, or it may be
varnished or worked upon by the artist's hand to any desired extent.
My Invention is applicable to photographs produced in various ways,
such as the carbon process, enlargements by the camera, by the Wood-
bury process, or by any other known methods by which a photograph
can be obtained on glass, having the same or a similar appearance on
cither side. Suitable photographs for this purpose can also be produced
by printing from positives as well as from negatives by using what has
been called the dusting-on process, and by using the proper vitreous or
enamel colours. This process becomes available for the decorations of
glass, enamel, or ceramic surfaces, and the colours may be burned in.
I can also vary my Invention by applying the colours immediately
to the surface of the canvas or other material by printing, painting,
stamping, or staining the colours on any desired substance or surface,
and then fixing, or cementing, or producing the transparent photograph
on or upon such coloured or prepared surface or surfaces.
on the 30th September 1870. -
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
MCCRAW, Photographer, 9, West Catherine Place, Edinburgh, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirty-first day of March, in the year of 3

page_text: our Lord One thousand eight hundred and seventy, in the thirty-third
year of Her reign, did, for Ierself, Her heirs and successors, give and
grant unto me, the said William McCraw, Her special licence that I, the
said William McCraw, my executors, administrators, and assigns, or such
others as I, the said William McCraw, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to
time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN PHOTOGRAPHY BY
PROCESSES WHICH COMBINE PRINTING, PAINTING, AND TRANSFERBING, FOR THE
PRODUCTION OF CROMO-PHOTOGRAPHS," upon the condition (amongst others)
that I, the said William McCraw, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said William McCraw, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement, that is to say :—
In carrying out my Invention I use ordinary negatives, but I do not
usc ordinary paper prints.
The Printing. I proceed in the first place to produce a print or
copy from a negative that is independent of or that can be separated
from the glass or paper or other temporary support necessary to its
formation. For this purpose I coat one side of a glass plate with
collodio-chloride of silver, having a good body of collodion, and having
dried and fumed the surface with ammonia I print strongly and tone the
image if necessary with solutions of all or any or either of the chlorides
of gold, platina, and sodium. With these three the operator with a little
practice can produce a picture of almost any tone or colour, red, blue,
or yellow, or combinations of them.
To describe another suitable method:-I coat a plate of glass with
plain collodion, and immerse in water for some minutes; I then pour
over this wet surface a mixture of honey, albumen, and saturated

page_text: solution of bi-chromate of potass in water, about equal parts of cach, or
I use other well-known substitutes, such as sugar, gum, and bi-chromate
of ammonia. This prepared plate is dried at the fire in darkness, and
after exposure to light under a positive photograph colour in powder is
applied with a soft brush to develope the picture. It is now immersed in
water, slightly acidulated with sulphuric acid, or a few drops of strong
ammonia in the water serves the same purpose of clearing away the
yellow chromate. This picture when dry is ready for the next process.
For pictures of this kind instead of using a negative I employ a positive,
or print from a negative obtained with collodio-chloride of silver, as
already described.
There are many other well-known methods or processes for producing
prints suitable for this purpose, namely, the ordinary photographic
collodion processes, wet or dry, including enlargements by the camera,
the carbon process, the Woodbury process, or by any other method by
which a photographic copy can be made that has the same or a similar
appearance on either side when produced upon glass. Having obtained
the print on glass I proceed to the
Painting. I use the artist's oil colours mixed with Japan gold size, or
other quick driers for saving time. I can also use water colours to
begin with, as in the case of a portrait, for coloring the lips, articles of
jewellery, or for remedying spots or defects, as this can be dried at once.
I then paint over the whole with the appropriate local colours of the parts,
and the painting may be completed at once. It must be understood that
the effect is to be observed from the other side, which can be readily
done when the picture is on glass. After a little practice, however, in
this way some of my assistants prefer to apply the colour to the film
photograph supported on paper and removed from the glass by pasting
white paper on the film, using starch, sugar, or gelatine, or a mixture
of these in water. This is allowed to dry, and can readily be removed
from the glass at any time by slightly moistening it again. This has
the advantage, with others to be after noted, of giving the picture in
its true relative positions when finished in the case of direct prints on
glass from negatives being used.
Transferring. The picture when dry is ready to be transferred to canvass
or any other suitable surface or material, and is in fact precisely in the
condition of a picture ready to be lined, which is an ordinary operation
of the picture liner. I smear the painted surface as well as the surface

page_text: of the canvass with what is known to picture liners as lining paste, a
mixture of gluc and flour and Venice turpentine, the two pasted surfaces
being pressed together. The excess of paste is expelled by passing over
it a smoothing iron heated to about 130° degrees, and soon after the
picture readily parts from the glass. It may be remarked that if the
picture be removed from the glass whilst still warm and moist a duller
surface is got then when the picture is not detached for a day or two,
when it then receives or partakes of the quality of the surface of its
support, whether dull or polished. For the sake of clearness I have
hitherto spoken only of painting, the film as still adhering to glass, but
in many cases it is an advantage to use the paper supported film for
painting on, as in the case of transferring the picture to a rigid surface,
such as a panel, and it becomes very important when a number of copies
of the same subject is required, as in the case of reproducing works of
art, as the colours can then be applied by chromo-lithography or other
known mechanical means, and when the picture has been trimmed at
the edges and transferred with the painted side down, as already
explained, to paper, cardboard, or other permanent support, the paper
temporarily covering the picture is easily removed by passing over it a
sponge dipped in tepid water.
By another application of the same principle I can produce vitrified
enamel chromo-photographs. In carrying out this part of my Invention
I produce a vetrifyable film photograph by either of the well-known
methods known severally as Grune's method and the dusting-on process,
I now cut from a large globe of blown thin soft glass a piece of the
required size and shape; I cover the convex side with this film, and
after filling up the concave with stucco I subject this to heat in the
muflle of an enameller's furnace. When cool I paint this picture with
appropriate enamel colours and again fire; this thin glass bearing the
painted picture is returned to the muffle picture side down, and allowed
to fall over a white enamel surface prepared to receive it. The edges
can now be grooved and polished to fit any setting.
Having thus described the nature of my Invention, and the manner
of carrying the same into effect, I would observe that I do not confine
myself to the precise details herein described, as they may be modified
as circumstances may require; but what I claim as novel and desire to
be secured to me by the herein-before in part recited Letters Patent is,
the production of chromo-photographs by introducing colours between

page_text: the photograph and its support, such photographs being embodied in a
transferable transparent film or medium, the support being opaque.
In witness whereof, I, the said William McCraw, have hereunto
set my hand and seal, this Twenty-eighth day of September, in
the year of our Lord One thousand eight hundred and seventy.