Year: 1888

page_text: Date of Application, 17th Jan., 1888
Specification Accepted, 17th Feb.. 1888
1, WILLIAM PHILLIPS THOMPSON F.C.S..M.I.M.E. of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both in
the County of Lancaster, and 323, High Holborn, in the County of Middlesex,
Civil Engineer, 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 :-
This Invention relates :-
1st. To the preparation and application of oil colours which will harden at all
times by heating them a little.
2nd. To the artificial hardening of these oil colours, after they have been laid on,
by heating them for a period, varying from a few seconds to a few minutes.
3rd. To the preparation of a painting ground, which at the ordinary temperature
does not allow the binding medium of the oil colour to pass through, but at a.
higher temperature absorbs this binding medium.
4th. To rendering the above named painting ground pervious, after it has been
used, by means of heat.
5th. To the preparation and application of a new medium for. oil paints, which can
harden after a short application of heat.
Formerly a great waste of time and many difficulties were connected with oil
painting. By using a non-absorbing painting ground, as is done at present, every
layer of colour must first dry before a new one can be applied, and in the application
of absorbing painting ground, as used in the earlier centuries, great haste and skill
were required on the part of the painter, because the said painting ground absorbed
the oil out of the colours and. rendered them worthless as regards the melting
thereof.

page_text: By this new process the loss of time, which results from the slow drying process is
avoided, and on the other hand, the difficulties of manipulation, which are met with
in the application of paint to an absorbing ground, are remedied.
When using this process it will be found that an oil painting can be made from
beginning to end without an interruption, just as is the case in water colour
painting.
The new process consists, firstly, in adding to the oil paints suitable substances,
which enable them to harden after being heated for a short time; secondly in effecting
this hardening on the surface of the picture after a coat of paint has been given and
before the colours dry naturally; thirdly, in making the absorbing painting ground,
as hitherto prepared, impervious to oil at ordinary temperatures, but pervious to it at
a higher temperature and consequently capable of absorbing oil on being heated ; and
lastly, in adding to the painting mediums hitherto used in oil painting substances
which render them hard after a short heating.
1. The hardening of oil colours
As hardening substances the following may be employed :, Carnauba wax, Palm
wax, or shellac, or a mixture of these substances.
The colouring matter is first of all mixed with one of the foregoing substances, or
with a mixture of the same, and then ground very' fine and heated to a temperature
of about 100 degrees to 120 degrees Centigrade, so that the wax melts and thoroughly
permeates the colouring matter. After cooling, one of the binding mediums used for
ordinary oil colours is added, finely divided in the same manner as is done with the
usual oil colours.
Or the colouring matter is first of all mixed with the binding medium usually
employed for ordinary oil colours, and then finely ground, after adding shellac
Carnauba wax or palm wax or a mixture of these substances.
The proportions by weight by the colouring matter and hardenable material
depend upon the degree of hardness which is to be obtained by heating. Colours
which are principally laid on with a brush should be as firm as tallow, after hardening
on the surface of the picture, and they require from about 2 to 10 per cent. of their
weight of the said hardenable material; whilst colours which are to be worked upon
with the spatula, after the hardening of the painting, will require an addition of these
hardenable materials, varying from about 10 to 30 per cent. of the weight of the
colouring matter.
2. The artificial hardening of oil painting :-
The treatment of the hardenable oil colours is as follows:-The coating of
colour is laid on the surface of the picture in the same manner as in the case
of ordinary oil colours. The hardenable colours, if left to themselves, keep moist
and soft on the pallet and picture as long as the ordinary oil colours, so that
it is possible to paint with them in a moist state just as long as with ordinary
oil colours. The difference between the new process and that hitherto used in the
painting art consists in this :-The moist coating of paint can be hardened at once,
on the surface of the picture, as soon as another coating has to be applied over the
first coating.
For this purpose the said coating of paint is heated for a short time, varying from
a few seconds to a few minutes, and to a temperature of about 40 degrees to 80 degrees
centigrade. A reflector is advantageously employed for this. After this heating the
colour is allowed to cool completely.
By this process the previously soft, moist colour passes into a hardened state, so that
it cannot run off when in contact with the brush, and can serve as a base upon which
to lay the new coating.
This hard state of the colours is not synonymous, and must not be confused with,
the natural drying up of the same. The colours require as much time to dry up,
after the artificial hardening, as the colours in their unhardened state, or as the
⚫ ordinary oil colours, namely, a time varying from one to several days, according to
season of the year.

page_text: 3. Preparation of the painting ground
-
This preparation is effected either with or without the use of the well known
absorbing painting ground.
In the first case the process is as follows :―
The well known painting ground, whether it be canvas, cardboard, paper or wood,
is provided with a coating, which at the ordinary temperature is impervious to oil, whilst
at a higher temperature it permits the penetration of the oil.
The following substances may be used for this purpose:-wax, hard fat, hard fatty acids,
mineral wax, paraffin, resin, gum, or gum-resin, or a mixture of these substances.
The manner in which this coating is applied to the absorbing ground is, for the
process now under consideration, unimportant, or is only important in as far as any
of the methods can be employed with the same ease. By way of example, a method
of coating which is easily executed may be described.
Dissolve, by the application of heat, 1 part by weight of wax in about
4 to 6 parts by weight of turpentine oil, and let it cool completely. Lay a
moderately thin coating of this on one of the absorbing painting grounds
hitherto used in oil painting, and lay the said ground aside to let the turpentine
evaporate. After a few days, coat the surface again with a pigment made
of one part by weight of gum-elemi, in about 4 to 6 parts of spirit. When this
coating has dried, expose it for a few moments to steam at 100 degrees Centigrade.
This will cause the coating of wax and gum-elemi to penetrate thoroughly into the
upper surface of the painting ground. After the evaporation of the adhering
moisture, the painting ground is ready for use. When a new painting ground is to be
prepared without the conjoint use of an already existing absorbing ground, one
proceeds as follows:-
Pulverise the well known lean priming mass hitherto used for the purpose of
priming canvas cloth, (and consisting of clay chalk, gypsum, bôle or colouring matter,
and of a binding medium with about 25 per cent. of wax, mineral wax, paraffin, hard
fat or hard fatty acids, or a mixture of these substances), make a pigment of it and
lay the same on the fabrics, paper, paste board or wood, and when it is dry heat it for a
short time at a temperature of about 20 degrees Centigrade, and so cause a complete
penetration of the priming into the body of the ground.
4. Rendering the new painting ground pervious.
The new ground is coated with paint in the same manner as is the case with
the usual impervious ground. Here also the paint remains moist and fit for
painting just as long as in the case of the old impervious ground, so that one can
paint with them in a moist state just as long as with ordinary oil colours. But as
soon as the painter wishes to paint over the first coating, or wishes to harden the
painting, he exposes the new painting ground and coating of paint for a few minutes
to a higher temperature say about 40 degrees to 80 degrees Centigrade. The layer,
which was previously impervious, becomes pervious at this temperature, so that a part.
of the oil contained in the colours penetrates into the painting ground, in consequence
of which the coating of paint becomes hard and suitable for painting thereon. The
heating is effected best by means of a reflector.
When the paints (which have, in consequence of the absorption of oil, become dull)
are to reassume their original brilliancy, a coating of varnish of essence of savory is
applied in the usual manner.
The hardening of the colours described in No. 2 will be greatly enhanced by the
method described here, under No. 4, for the purpose of treating the new painting
ground.
5. The new paint medium.
This is used to thin the colours a little on the pallet when fine painting has to
be done.
The preparation is formed by adding about 5 to 20 per cent. of Carnauba wax
or palm wax to one of the painting mediums now in use, and by afterwards grinding
this mixture.

page_text: Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is :-
1. The process, substantially as described, of manufacturing oil colours by first,
finely grinding the colouring substance with shellac, carnauba wax, or palm wax, or a
mixture of these substances, by afterwards heating the resultant mixture to a
temperature of about 100 degrees to 120 degrees Centigrade, and then letting it cool,
and by finally re-grinding it with a known binding medium, such as is used
with ordinary oil colours; whereby oil colours are produced, which, at ordinary
temperatures, are of a similar consistency to the usual oil colours, but barden after
having been submitted for a short time to a temperature of about 40 to 80 degrees
Centigrade.
2. The method, substantially as described, of preparing oil colours, by adding shellac,
carnauba wax, or palm wax, or a mixture of these substances to the well known oil
colours, and by grinding the whole; whereby resultant oil colours are obtained, which, at
ordinary, temperatures, are of a similar consistency to the usual oil colours, but
become hard, after having been submitted for a short time to a temperature of
about 40 degrees to 80 degrees Centigrade.
3. The production of oil colour paintings and similar painted surfaces, by the
following process, which consists: 1st. in the preparation of hardenable oil colours,
which at the ordinary temperature are of a similar consistency to the usual kinds of
oil colours, but harden after being heated for a short time to a temperature varying
from about 40 degrees to 80 degrees Centigrade; 2nd, in the coating, with these
hardenable colours, of painting grounds or other surfaces of any description used in
the painting art; and 3rd, in the artificial hardening of these hardenable colours,
(after they have been laid on the surface to be painted), by heating the painting ground
and the colours thereon, for a short time at a temperature of about 40 degrees to
80 degrees Centigrade, substantially as and for the purposes described.
4. In the production of oil colour paintings or similar painted surfaces, the
application to their painting grounds of hardenable oil colours, such as are herein
described, and the subsequent hardening of said colours by heating them for a short
time at a temperature of about 40 degrees to 80 degrees Centigrade and by afterwards
letting them cool, substantially as described.
5. In the production of oil colour paintings or similar painted surfaces by means of
hardenable oil colours such as are herein described, the mixing of carnauba wax or
palin wax, with the paint mediums hitherto used in the painting art, and the subse-
quent grinding thereof, whereby a paint medium is produced, which will harden
when heated to a temperature of about 40 degrees to 80 degrees Centigrade, and by
means of which the colours may be thinned down.
6. The method, substantially as described, of preparing painting grounds or
surfaces for use with hardenable oil colours and mediums, such as are herein described,
which consists in applying to the usual absorptive surfaces employed for painting
purposes, a coating of wax, hard fat, hard fatty acids, mineral wax, paraffin, gum,
gun resin, or a mixture of these substances, whereby the said painting grounds are, at
ordinary temperatures, rendered impervious to the binding medium of the hardenable
colours laid thereon, but absorb part of this medium at a higher temperature of about
40 degrees to 80 degrees Centigrade.
7. The method, substantially as described, of preparing painting grounds or
surfaces on which hardenable oil colours can be used, such as are herein described,
which consists, 1st, in grinding the lean priming mass (hitherto used for priming
canvas) with wax, mineral wax, paraffin, hard fats, or hard fatty acids, or a mixture of
these substances; 2nd, in applying the resultant compound to fabrics, wood, paste-
board or paper, and 3rd, in heating the latter up to about 120 degrees Centigrade,
whereby the said painting grounds are, at ordinary temperatures, rendered im-
pervious to the binding medium of the hardenable colours laid thereon, but absorb

page_text: part of this medium at a higher temperature of about 40 degrees to 80 degrees
Centigrade.
8. The production of oil colour paintings or similar painted surfaces by the
following process, which consists, 1st, in preparing painting grounds and hardenable
oil colours in the manner or manners hereinbefore described and claimed ; 2nd, in
applying these hardenable oil colours to the aforesaid prepared painting grounds; and
3rd, in the artificial hardening of the said colours by submitting the prepared painting
grounds, and the hardenable colours thereon, for a short time to the influence of heat
at a temperature of about 40 degrees to 80 degrees Centigrade, substantially as
and for the purposes described.
WM. P. THOMPSON & Co.,
Agents for the Applicant.