AN IM- PROVED MODE OF PREPARING AND EMPLOYING CERTAIN COLORS AND MATERIALS FOR PAINTING
Year: 1847

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
MURDOCH, of Staple Inn, in the County of Middlesex, Patent Agent, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Tenth day of March
(One thousand eight hundred and forty-seven), in the tenth' year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said James Murdoch, my exors, adiňors, and assigns, Her especial license,
full power, sole privilege and authority, that I, the said James Murdoch,
my exors, admors, and assigns, or such others as I, the said James Murdoch,
my exors, admors, or assigns, should at any time agree with, and no others,
from time to time and at all times during the term of years therein expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, the Invention of "AN IM-
PROVED MODE OF PREPARING AND EMPLOYING CERTAIN COLORS AND MATERIALS FOR
PAINTING," communicated to me by a certain foreigner residing abroad; in
which said Letters Patent is contained a proviso, that I, the said James
Murdoch, shall cause a particular description of the nature of the said Inven-
tion, and in what manner the same is to be performed, by an instrument in
writing under my hand and seal, to be inrolled in Her said Majesty's High
Court of Chancery within six calendar months next and inmediately after the

page_text: date of the said in part recited Letters Patent, as in and by the same,
reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I have
ascertained and set forth the nature of my said Invention, and the manner in
which the same is to be carried into effect, in and by the following description
thereof. And that the same may be more readily comprehended, and the results
of the Invention more readily seen, and also with the view of pointing out
more strongly the difference existing between the old processes, in respect to
the use of certain colors, and the processes constituting the Invention with
respect to the employment of certain other colors, as well as to determino the
true characteristics of the Invention, I have thought it best to preface the
practical explanations with the following preamble :-
Everybody is aware of the fatal rapidity with which pictures painted in oil
become changed,-everybody is grieved at the thought that masterpieces of
the greatest artists must after a time lose their freshness and their primitive
colors, and that at length they will not be recognizable; the still more rapid
alterations of the colors in the painting of buildings and in paper hangings, &c.
are not less to be regretted in an economical and manufacturing point of view
than the former are in regard of the arts. It must be added, that the principal
substances in the scale of the tones of painting at present employed are violent
poisons, which, both in the preparation and the subsequent use, frequently
occasion serious accidents. These inconveniences having been long more or
less felt, many attempts have been made by men of science to discover other
substances which might serve as substitutes for the most dangerous and
fugitive of those in the scale at present in use in the pictorial art, and in those
manufactures in which colors are employed. Many causes, which I shall
presently point out, have hitherto prevented the success of these attempts, but
I must first state the problem generally and with exactness.
The principal and fundamental colors in painting, and from which all the
others are prepared, are the white, yellow, green, blue, red, and black. The
most important of all these colors, and to which it is most desirable to impart
fixity and inalterability, is the white, which enters into the composition of
almost all tones; yellow, which next to white is the clearest color, ranks
second. The blues, reds, and blacks being obtained from substances which are
generally fixed, unalterable, and not poisonous, and the greens being obtainable
by the mixture of blue and yellow; it results, as a general system, that the
problem of the reform of the scale of colors is principally in the substitution
of whites and yellows, which are fixed, unalterable, and not poisonous, for the
whites, and yellows at present in use.

page_text: The whites at present used in painting in oil are white lead, or ceruse, and
"silver white," which is merely a fine kind of white lead. These whites it is
well known are very subject to alteration from sulphurous emanations, which
change them quickly to yellow, and even to a dirty black. The preparation
and handling of these substances it is likewise well known are highly
dangerous.
The yellows are obtained from ochres, which are fixed and harmless, of "stil
de grain," too subject to change to admit of being employed to advantage in
oil painting; and, lastly, yellows with a base of lead, or which contain it; the
ochres affording only heavy tones. The system of preparing the yellow tones
and their numerous combinations depends in fact upon the chromates of lead,
but the yellows prepared from lead are subject to precisely the same incon-
veniences as the whites prepared from lend or ceruse.
The blue tones being the produce of cobalt, ultramarine, Prussian blue, &c.
are unobjectionable, although the last-named substances is not unalterable
under certain circumstances.
The reds are nearly in the same position, being obtained from vermillion
and cimabar, which are very fast colors, nevertheless substitutes are required
for minium and mineral orange on account of susceptibility of change.
The trade greens are worthless. Verona green is very dear. All the
greens with a copper base, besides being strong poisons, are also as liable to
change as the whites and yellows from lead, by the action of sulphurous
vapours, "aqua secunda," &c.
The blacks are not open to objection.
It results, from this review of the scale of tones, that the desired reform, in
order to be complete and satisfactory, requires the means of preparing the
following colors in a large or wholesale way :-
First, a white unchangeable and not poisonous as a substitute for white
lead.
Second, a yellow possessing the same advantages to replace the lead
yellows.
Third, a fast red fit for producing the flesh tones and other tones, which
could be produced by the combination of various yellows with the mineral
orange if this latter color were not so changeable that it has been found
necessary to abstain in a great measure from employing it.
These three colors, combined with those of the present scale which do not
require substitutes, evidently furnish a complete system of fixed and un-
alterable tones, and fully solve the problem proposed at the cominencement of
this memoir. This, however, is not all; most oil colors require, to dry them,

page_text: that the oily substance should be prepared with some drying substance. The
substance most generally employed for this purpose is litharge or oxide of
lead dissolved in linseed oil by long boiling, but it would be to no purpose to
have banished lead and copper from all the tones if lead is to enter into the
composition of the dryer. In order, therefore, to complete the reform in
question, it becomes necessary to find a dryer as unalterable and as harmless
as the colors of the new scale.
Now that the necessary conditions of the reform of the substantive bases,
have been stated, it will be easy to perceive the reason why all previous
attempts to solve the problem have failed. The problem had, in truth, never
been clearly stated or completely considered. A French philosopher (Guiton.
de Morveau) who has considered the question with great intelligence and
perseverance, but who was not a practical man, missed the solution, he con-
fined himself to the white only; and although he fully felt the objection to the
Jead dryer, and strongly recommended avoiding the use of it by substituting for
it the white of zinc, he did not get rid of this dryer, which was a great obstacle
to the introduction of the new white which he proposed.
Lastly, to render the white unchangeable, but to admit the principal of.
change to enter again into the general system of tones by the yellow and all
its combinations, and by the greens of copper, as also by the dryer, would not
have been a solution of the question.
These considorations fully explain why, as I have already stated, previous
attempts have been fruitless. This brings me to mention that I obtained a
Patent, which was sealed Eleventh day of February, One thousand eight
hundred and forty-six, for "A Mode of Manufacturing Oxide of Zinc," and to
observe, that the processes herein-after described combined with those con-
stituting the object of the Patent of February Eleventh, One thousand eight
hundred and forty-six, present a complete system of reform of the elements of
painting.
The present Invention, therefore, relates, firstly, to the employment in
paintings of all kinds of certain colors not hitherto employed, as also of the
mixture of such colors either with the oxide of zinc or with other colors which
do not contain copper or lead.
Secondly, to a dryer, in the preparation of which oxide of lead is not
employed.
Thirdly, to the improvement of polished painting by means of substances
herein-after pointed out joined to the oxide of zinc.
In consequence, and the better to ascertain and determine the present
Invention, I declare that it consists,-

page_text: Firstly, in certain processes for manufacturing on a large scale zinc yellow,
barytes yellow, antimony red, and zinc green.
Secondly, the employment of these colors for painting in general upon cloth,
wood, walls, paper, &c.
Thirdly, in the mixture of these new colors, either in their application or in
the manufacture, with such of the colors commonly used as contain neither
lead nor copper, so as to complete the scale of unalterable colors.
Fourthly, in the employment of the unalterable colors with the oxide of zinc,
which is likewise unalterable, and which thus mutually aid each other in their
preservative effects.
Fifthly, in the composition of a new dryer, by means of a metallic peroxide
not affected by the action of sulphuretted hydrogen, principally the peroxide
of manganese, forming a substitute for the common dryer prepared with
litharge, ceruse, &c.
Sixthly, in the execution of polished painting both by means of the colors
before mentioned, according to the tints, and by the employment of zinc white
as a substitute for white lead.
Seventhly, in the application of the colors and the accessories connected
therewith to the manufacture of paper hangings, and of enamelled, glazed, or
watered cards.
I now proceed to describe the processes by which I manufacture the colors
above mentioned, as well as the manganesian dryer, together with the
directions necessary for executing polished painting.
Manufacture of zinc yellow.-To manufacture economically and upon a
large scale zinc yellow (chromate of zinc), three operations are required: the
first gives a color approaching to the yellow, called "marigold yellow;" the
second gives a lemon yellow; the third gives a product which partakes of the
two former tints but of a paler tone. To prepare the marigold yellow, I tako
one hundred and twenty-five pounds of bichromate of potass and dissolve it in
from seven hundred to eight hundred pounds of water heated in a copper
boiler, I then pour into the liquor about sixty pounds of "white" of zinc,
previously diluted in water to a clear cream, and passed through a sieve. This
operation should be performed in wooden vats lined with zinc (or other
suitable vessels) I leave the mixture to stand from twenty-four to thirty-six
hours, taking care to stir it frequently during that time; I then return the
whole into the boiler and boil it for an hour; it is then to be poured again
into the before-mentioned vats and allowed to settle, and the precipitate being
collected is washed, set to dry, and made up into cakes or lozenges.
Lemon tint. The decanted water resulting from the preceding operations,

page_text: as well as the water of the first washing, are heated together in a boiler, and
a solution of sulphate of zinc is poured therein. The said solution is made by
mixing about seventy-five pounds of oxide of zinc diluted with water and
passed through a sieve, with forty-four pounds of the sulphuric acid of com-
merce of the strength of about 65°. This sulphate is easily made in wooden
vessels by pouring the acid in by portions at a time into the clear cream of
oxide of zinc and stirring it well. The contents of the boiler are then boiled
for about an hour, and afterwards placed in the vessels lined with zinc, and
therein allowed to settle; after which the deposit is collected, washed, and left
to dry, and then made up into cakes or lozenges, as in the preparation of the
preceding yellow.
The pale tint. In this case, as in that of the citron tint, in order to extract
as much as possible from the original materials, the decanted water from the
second operation, as also the first washings from the two former operations,
are put together into the boiler, as before, and sulphate of zinc, composed of
fifteen pounds of oxide of zinc and seven pounds of sulphuric acid of commerce,
is poured therein; the whole is boiled together and subjected to the same
subsequent operations as are described above in relation to the preparation of
the first two yellows.
What is claimed in this mode of manufacturing yellows of zinc is, firstly, the
neutralizing the bichromate of potass by the oxide of zine; and, secondly, the
employment of the oxide of zinc to make sulphate of zinc, and at the same
time more completely to precipitate the chromate of zinc.
Barytes yellow. Referring back to the basis of the processes already
described for preparing the chromate of zinc and taking the chloruret of
barium free from iron, and the neutral chromate of potass and of soda, it will
be sufficient to give the following formula :-Into a solution of chloruret of
barium free from iron pour a solution of the double chromate of potass and
soda until there is no further precipitate, wash the product and dry it by a
stove. The proportions in which the materials are to be employed are one
hundred pounds of chloruret of barium to eighty-two or eighty-four pounds of
the double neutral chromate of potass and soda. By this means the Inventor
has succeeded in manufacturing economically and in the large way, and
thereby rendered applicable for the purpose of painting, barytes yellow, which
has hitherto been known only as a product of the laboratory, or rather as a S
scientific product.
Compound colors.-By this term is designated the different tones obtained
by the mixture and combination of the colors, of which the preparation is
described in this Specification, with colors before in use taken from those which

page_text: contain neither lead nor copper. In fact it will be understood that by means
of the white and the chromate of zinc, the chromate of barytes and the red
sulphuret of antimony mixed and combined with other colors heretofore in use,
an infinite variety of tones may be obtained, and which are not acted upon by
sulphuretted hydrogen. To enumerate them here would be to give an entire
nomenclature. I would, however, mention, amongst the yellows Roman yellow,
brilliant yellow, antimony yellow, Mars yellow, Indian yellow, Naples yellow,
mineral yellow, and chrome yellow of several shades, colors which may all be
obtained by the combination of the colors which are the products of the
processes herein-before described, with other known colors, as raw terra sienna,
&c. as may be requisite. As for the greens, known by the names of dark
English green, brilliant English green, Milori green, verditer and verdigris,
they are obtained in the same way as the yellows by mixing therewith more or
less blue. As regards the mode of preparing these colors, the combination
may be made with the primitive colors whilst in the state of paste and before
they are carried to the stove, or they may be mixed after the materials are
ground. It will be seen that the principle of the combination of the compound
colors consists in the mixture of the white of zinc and of the colors prepared
by the new processes herein described with colors which are not changed by
the action of sulphuretted hydrogen, or by other causes, for the purpose of
producing tones or shades of color which hitherto have been unobtainable
unless by the means of a combination with colors having for their base lead
or copper, and therefore liable to damage from the destructive agents which
the improved compound colors completely resist.
I claim, in respect to this part of the Invention, the manufacture of all these
unalterable compound colors by the combination of my patent colors, either
with each other or with unalterable colors heretofore known.
Orange red. Sulphuret of antimony. The preparation of this sulphuret
by the process herein-after given is presented as producing a color not hereto-
fore employed in painting. Its unalterability, whether by light, by damp, or
by sulphuretted bydrogen, has caused it to be included in the new scale of
colors, and under this point of view, as well as with regard to the means
herein-after described, it will be perceived that this new product is calculated
(like others of a similar nature, and hitherto unknown in commerce,) to assist
the new system of painting in zinc.
Natural sulphuret of antimony, reduced to powder and as free as possible
from lead, is exposed in earthen vessels to the action of hydrochloric acid,
purified from lead and assisted by heat. The addition of acid is continued until
the whole of the sulphuret is dissolved, five to six parts of acid being in general

page_text: required to one part of sulphuret. As soon as a first operation is effected, the
hydrosulphuric acid which is disengaged from a second operation serves to
prepare the sulphuret of antimony in the following manner:-When all
the sulphuret is dissolved, the liquor, which is the perhydro-chlorate of anti-
mony, is decanted into earthen or wooden vessels pierced with holes at
different heights; the strength of the decanted liquor is ascertained, and
by the addition of water or of acid it is brought to mark by the common
French ariometre 13° to 17°, according to the shades required. The required
strength being attained, the liquor is put into suitable vessels, and a current of
bydosulphuric acid is passed through it, which produces the orange red of
antimony.
Note. The specific gravity of 15° suits well with the new scale of colors,
but I claim all shades which may be obtained by saturation from 18° to 17°.
I must observe that the tubes which plunge in the solution of antimony should
be of glass, and of large diameter, so as not to become blocked up by the red
sulphuret of antimony, which is formed by the contact of sulphuretted
hydrogen and the perhydrochlorate of antimony. The liquor should be
frequently stirred with a wooden spatule, and the vessel in which the action is
going on should be kept covered, or a communication should be established
between several, so as not to allow the sulphuretted hydrogen to escape, which
would injure the workmen; also the last tubes should plunge into a cream of
lime to absorb the excess of gas. When there is an excess of sulphuretted
hydrogen in the vessels, the current of gas is suspended, the precipitate of the
sulphuret of antimony which is formed is allowed to settle, and is washed by
decantations several times; it is then spread upon cloths and washed thoroughly
until the water runs off tasteless; the precipitate is then dried at a gentle heat,
and by a stove, the heat should be very moderate, not exceeding 100° to 120°
Fahr, otherwise the sulphate becomes anhydrous and turns black. The
importance of carrying out the process with exactitude will therefore be
apparent.
Zinc green. To obtain zinc green, a hot solution of forty-nine pounds of
pure and dry sulphate of cobalt is to be poured upon two hundred and forty-
five pounds of oxide of zinc slacked with as little water as possible; the
whole is well stirred to mix it thoroughly, and is dried, and is then calcined
for about three hours in a muffle furnace heated to bright red, and after
letting it cool a little it is thrown into water, is washed, and then dried.
I claim, for the purpose of making this green, the employment of the oxide
of zinc direct mixed with any salt of cobalt.
Dryer. This dryer, intended to cause the oxide of zinc to dry, as it dries

page_text: more slowly than oxide of lead, has principally for its object, by the nature of
its composition, to harmonise with the colors above mentioned, that is to say,
which are insensible to the action of sulphuretted hydrogen. It is composed
of a metallic peroxide, selected not only from those which can be employed in
commerce from their cheapness, but also from those which are not affected by
the deleterious gases, and which have the property of yielding a portion of
their oxygen to a great number of substances in certain cases. Thus, for
example, the peroxide of manganeso in particular may be selected, combined
with linseed oil, according to the formula of preparation hereafter given. A
compound is thereby obtained of manganesed oil, capable of being used with
white of zinc, and with the colors having a base of zinc, or any other. Boil
purified linseed oil six to eight hours, then for two hundred pounds weight of
the boiled oil add ten pounds of the peroxide of manganese of commerce,
pounded, and preferably in a pulverulent state, in order that particles in
suspension may not injure the freshness of the clear tones of the painting.
Boil the mixture five to six hours, taking care to stir the materials to prevent
the oil becoming carbonised at the bottom of the vessel, and the manganese
sticking to the bottom, unless the latter substance is placed in a bag, as is done
with litharge. The manganesed oil is allowed to cool, and then filtered, in the
same way as litharged oil. This dryer is added to the color prepared with the
zine white, the proportions varying from 1 to 2 of the weight of the pre-
paration, according to the rapidity required in the drying, or according to the
temperature and state of the atmosphere. I would here observe, that although
manganese may be used in the state of powder to be mixed with colors, as is
done with litharge, it is preferable, in order to obtain a more thorough mixture,
to mix the manganesed oil with the white of zinc in grinding the latter. In
this case the proportion of dryer should be to of the weight of oil.
The hydrated peroxide of iron may be substituted for manganese, as also
may certain other substances which contain more or less of manganese, as, for
instance, umber, but not with equal advantage. Also, according to the greater
or less depth of color in a painting, the manganese may be employed in the
state of peroxide, protoxide, sulphato, acetate, and carbonate.
Polished painting. This species of painting is employed to imitate marbles
and other substances susceptible of polish. By the ordinary process, in which.
colors having a base of lead or of copper are employed, not only does this kind
of painting turn yellow if it is white, or loses its freshness of tone, but it also,
requires considerable labour.
It is not necessary for me to go into all the processes of execution.
hitherto employed with the ordinary colors; I shall merely point out the

page_text: mode of proceeding when oxide of zinc and other unalterable colors are
employed in polished painting. Several coats of oxide of zinc of greater
or less thickness are laid upon the object to be polished painted, the oxide
being mixed with manganesed oil; the surface thus obtained is rubbed
with pummicestone, adding the required tints in unalterable colors of the
kind already described, and a polished painting is thus obtained as bril-
liant as that obtained by hard tints, by repeated paintings and varnish, which
are employed in the execution of polished painting in the ordinary process.
Polished painting is more employed for painting carriages than for house
painting, nevertheless, on account of the economy in the execution of the new
process, this style of painting is susceptible of great extension; on the other
hand, as no varnish is employed, and as the oxide of zinc is not affected by
sulphuretted hydrogen, polished white painting can now be executed which
will not turn yellow, and in like manner colored painting performed with my
unalterable colors will not become deteriorated.
Paper hangings.-The application of the new colors and of their compounds
mixed with the white of zinc, and with the improved dryer, to the manufacture
of paper hangings, presents the same advantages in this branch of manu-
facture. The white grounds, dead polished, watered, or satin-like, will no
longer turn yellow, the gold even will keep better, and the brilliancy of the
colors printed upon paper will be as striking as in paintings done with the
pencil or brush. The employment of the new material does not call for any
change in the mode of manufacturing paper hangings as at present practised
with the ordinary materials; the result only differs.
Having thus described not only the basis of the Invention, but also the
various processes for carrying it into effeet, and having compared it with the
ordinary methods and processes, and shown the effects of its various applica-
tions, I shall conclude in stating what I claim in respect thereof; I claim,-
Firstly, the particular mode of manufacturing zinc yellow, barytes yellow,
orange red, sulphuret of antimony, and zinc green, as herein-before described
with relation to each of these colors.
Secondly, the application of these colors not hitherto known to painting
pictures, buildings, and other objects, whether upon stone, wood, plaster,
canvas, paper, &c.
Thirdly, the manufacture of compound colors, in the composition of which
enters zinc yellow, antimony red, barytes yellow, or zinc white.
Fourthly the compounding a dryer with linseed or other oil and manganese,
as also the processes herein-before described for that purpose, which dryer
called "manganesed oil," is intended to replace litharged oil, with a view to be

page_text: used in aid of the oxide of zinc, and of the colors which are not affected by
sulphuretted bydrogen.
Fifthly, the mixture of the dryer with the aforesaid colors, or of any of the
kind known as unalterable, in the case where such mixture would be required
in analagous mixtures of other colors and other dryers.
Sixthly, the application of the above-named colors mixed with the oxide of
zinc and the dryer above named to the manufacture of paper hangings, as
aforesaid.
Seventhly, the mode of executing polished paintings by means of the oxide
of zinc, as aforesaid.
Lastly, I claim the mixture as may be required of the ordinary colors
unalterable from the nature of their bases with those produced by the processes
herein-before described, and ground either with or without the dryer (which
mixture may be easily made at the time of using them), for exposing them to
sale, whether in cakes or lozenges, or in powder, or ground in oil.
In witness whereof, I, the said James Murdoch, have hereunto set my
hand and seal, this Tenth day of September, in the year of our Lord
One thousand eight hundred and forty-seven.
JAMES (L.s.) MURDOCH.
AND BE IT REMEMBERED, that on the Tenth day of September,
in the year of our Lord 1847, the aforesaid James Murdoch came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according to
the tenor of the Statute made for that purpose.