and while the paint is still fresh, sand half of it, then
notice what the consequences will be say in five years.
The unsanded lead will be in a bad state of chalking; the
lead and zinc will be in a better condition, but still will
begin to show signs of decay; while that part which has
been sanded will be on as tight as the day it was put there.
The silica did it. This is invariably the case; and as it is
a common practice for many places exposed to being
marred or defaced to be sanded, one will have little trouble
to find samples of it already so painted which have been
put on for many years. It can thus be seen and the results
ascertained without having to wait several years for it.

The good wearing qualities of the French and English
ochers are due to their being silicate ochers; they contain



WHITE PIGMENTS 51

a large percentage of silica in their base. (See the chapter
on ocher.) Had the silicate earth but the opacity of
white lead, it would be worth its weight in gold, as the
saying is, as a pigment for general painting; but it has
not that quality.

Many of the most valuable colored pigments are
natural earths containing a large percentage of silica in
their composition, which will be properly noticed under
the several headings to which they respectively belong.

BARYTA WHITE (BARIUM SULPHATE)
Composition and Provenance

Baryta white is better and more commonly known as
barytes in the United States. It is found commercially
of many different grades and qualities. It is obtained in
its natural state in many parts of the world. It is well
known under the form of " heavy spar," which is a heavy
crystalline rock. It is found in localities of many-vary-
ing geological formations. Near Quincy, Illinois, it is in
large quantities in the limestone formation of the bluffs
along the Mississippi River, also in the Blue Ridge region
of Virginia and elsewhere. Again, it is found in the zinc
and lead mines of Southwestern Missouri, Northwestern
Arkansas, Southwestern Kansas and the Indian Territory.
It is somewhat ludicrous, this finding of it in connection
with lead in mines as if that substance knew that later
on it should be made to parade as and become a still
closer neighbor of lead under its new form of "white
lead/' and made to renew an acquaintance with its old
neighbor where they had lain together for ages before
being disturbed from their peaceful slumber by the
miners.



52 MODERN PIGMENTS

Properties and Uses

Barytes is very transparent. It is the ideal trans-
parent pigment element, heavy spar being nearly as
transparent as glass. When ground in linseed oil, ordi-
nary barytes has no body. This can be best seen by the
mixing of barytes with oil, and of painting a board three
coats with it, the same mixed to the usual consistency
of paint for a like purpose. It will be found that these
three coatings, which had they been mixed from any of
the usual pigments would have covered the board per-
fectly, in this instance have not even hidden the tracery
of the grain of the wood. It will be safe to say that one
single coat of white lead would have covered the surface
of the board more opaquely than five coats of the barytes
paint would do.

That barytes must be a very heavy substance may be
surmised from the great weight of the heavy spar from
which it is prepared. It is by reason of this heavy weight
that it is the chief adulterant used to doctor up white
lead. It being nearly of the same specific gravity, it is
thus admirably adapted to pass inspection where the
lighter weight of better adulterants would be a "dead
give away" on account of the greatly increased size of
a package of a given weight. That is why whiting,
gypsum, etc., are so seldom used for the purpose of adul-
terating white lead. They would make entirely too much
bulk, and the fraud would be recognizable to a novice.
Therefore barytes has almost a monopoly as an adulter-
ant of white, its heavy weight entitling it to that eminent
position. Another requisite which is of as nearly as
much importance, is that of its great transparency. More
barytes can be added to white lead without muddying
its color, than of any of the earth whites of better body,



WHITE PIGMENTS 53

but which change the color of the pigments they are
added to, as has been already said of them.

Barytes is also the adulterant chiefly used in the mak-
ing of the cheaper colors in oil; this, however, more on
account of its transparency than that of its weight; as for
many of the lighter-weight colors it is greatly against it,
it makes the package look too small. Its transparency
usually decides the scales in its favor, as the chief make-
weight adulterant even for the light-weight colors, some
very light-weight adulterant being used in connection
with it to give more bulk. Its transparency does not
greatly affect the tone of the darker colors with which
it is used; and while it can be detected when the adul-
terated color is -used in making tints it renders them
less clear in tones it will hardly show in the color itself
in self-color painting.

In such extra light-weight colors as Prussian blue,
lampblack, etc., it cannot possibly be used alone, as it
would be an easy "give away; " so, as was said, it is usual
to marry it to a much lighter-weighted partner, but it
goes in just the same.

To show the capacity of barytes as an adulterant and
its transparency, fifty pounds of it can be added to one
pound of dry Prussian blue medium chrome yellow or
lampblack without changing the colors greatly. Thus
the enormous quantity of fifty to one is within the possi-
bilities in adulterating with it. While seldom used to
that extent, it is sometimes found in nearly that ratio in
the "cheap John" lines of colors in oil occasionally to be
seen frequently more in the cheap dry colors.

While upon the subject of adulteration it might be well
to say here that in a general way colors are not adulter-
ated to anywhere near the limit of the possibilities as
that of fifty to one. More frequently the adulteration






54 MODERN PIGMENTS

will be found to be one to one, three to one, or four to one
of the genuine color; the latter being the common one
in use, and recognized as justifiable for the proprietary
greens and many other colors which do not indicate
purity by any such claim upon their labels. This adul-
teration is, however, to such an extent, but will be found
in many whose labels would, to the unsophisticated,
create the impression that the colors were pure with-
out saying that in so many words.

As it is mainly as an adulterant that barytes has any
serious claims upon the attention of the readers of this
treatise, this is the side from which it is viewed.

Not so, however, of the artificially prepared baryta
white, which is better known to artists and decorators as
"blanc fixe." The latter is an excellent pigment for
water-color painting, and nothing of what has been said
of the natural barytes applies to that, except its lack of
opacity in oil; but even in that, it is head and shoulders
above the ordinary barytes. In water-color work, it
possesses a good body. It is a perfect white, absolutely
unalterable under all and any circumstances or conditions.
It is insoluble in the acids, and is not attacked by sulphu-
reted hydrogen gas nor any other sulphurous vapors.
It is of great value for uses wherever the painting is sub-
ject to such influences where most of the other whites
would be unsuited. Its absolute permanency recom-
mends it for the highest grade of decorative work,
and where the reputation of a man depends upon
the intact preservation of his work. It cannot be too
highly prized.

It has another very important qualification aside from
those of permanency and whiteness, in that it has a
peculiar texture that is entirely its own, and this remains
even in the tints made by its use. The same pleasing



WHITE PIGMENTS 55

peculiar finish cannot be reproduced with anything
else, no more than cotton can be made to have the
feel of wool.

The artists and decorators are the ones who are mainly
interested in its use. It is never likely to pass into the
hands of the general house painter.

The reader should remember to distinguish between
barytes and baryta white or blanc fixe. Dr. Dudley, chief
chemist of the Pennsylvania railroad, has had a great
deal to say of it, and is probably as good an authority
upon barytes in all forms as can be found the world over,
he having made that substance the subject of much
investigation and experiment. He says that some forms
of the atoms in certain grades of barytes are scale-like,
and overlap each other in such a way as to intercept the
rays of light, and that when colored up with proper pig-
ments the barytes does not show transparent. The
doctor must have come across a brand that is hard to
obtain outside of Altoona. The author has never yet
seen it, nor has he ever seen or heard of any one else who
has seen it in such a shape.

There is a legitimate use for barytes as an extender,
especially in such colors as the greens or chrome yellows,
which in their pure state are very strong. That state-
ment should be understood in this sense only: For
instance, one pound of pure chrome green or chrome
yellow is worth, say, 25 cents per pound. Another one
containing 80 per cent of barytes can probably be bought
for 12 cents. Now for solid painting the last will go about
as far as the pure, and cover the surface well. The latter
will be the cheaper for this use, so the extended green or
yellow is the most economical for solid painting. Where
colors, however, are bought for the making of tints, and
where the amount of coloring matter they contain is the



56 MODERN PIGMENTS

one thing most needed, the pure color will always be
found most economical.

The above concludes the list of useful white pigments.

Many others have come up from time to time, staid
a little while and were found wanting, or of less value than
these which have been noticed in the two preceding
chapters. They have about all disappeared, and the list
of them would read too much like an epitaph, and would
be a needless burden.



CHAPTER V
YELLOW PIGMENTS

OCHERS

General Characteristics

YELLOW ochers are natural earths found abundantly in
all parts of the known world. It is of small wonder then
that among the most ancient and earliest attempts at
chromatic embellishment that have been unearthed and
brought to light as a result of searches made in the
entombed remains of former civilizations, many objects
are found whereupon ocher had been used by some pre-
historic decorator.

This yellow was used in the making of many an ingen-
ious design upon the covering of the Egyptian sarcopha-
guses. In America the Aztecs especially, and the wild
tribes of Indians roaming the plains and mountains of
North and South America, used ocher also in such decora-
tions as they were able to design and execute.

The Aztecs being the better civilized of them all, one
would naturally expect more and better decorative work
from them than from the wild migratory tribes; and
they have not disappointed expectation, as remains
of their pottery and decorated household utensils will
show.

In Asia, ancient objects of Chinese and Tartaric origin
have tracings of it upon them. The Greeks and Romans
used it profusely; and so far there has not been a nation

57



58 MODERN PIGMENTS

found, where the earliest attempts at decorations have
been preserved, that ocher does not appear as one of the
pigments.

Of its uses to-day little need be said. It is a household
word, and its praises are sung by everybody interested
in using it, let him be painter, decorator, or artist. After
white lead, it is probably the one color that any of them
could least afford to discard.

Chemical Properties and General Character

All ochers are compounds or mixtures of several
ingredients or substances. The coloring matter they con-
tain is due to hydrate ferric oxide combined with an
earthy base which varies with each locality, and some-
times with every hill in the locality where they are found.
They will vary very much in the same vein of the same
bed. Different seams in the vein are often of diverse
composition, and are sometimes separated in the mining
operations.

There cannot be therefore any recognized standard
nor chemical formula for an article varying as much as
this does. They would have to be changed with each
new sample that was analyzed.

Notwithstanding so many variations, ochers may be
grouped into two general classes:

1. Those where the earth base holding the iron oxide
is chiefly of silicate earth.

2. The remaining ochers whose base consists princi-
pally of clay earths or alumina. There is a vast difference
between these two classes of ochers, not only in the work-
ing qualities of each, but in their tones and permanency.

Then there is between the two classes mentioned above
an intermediate one comprising such as vary in the
quantity they contain of either silica or alumina, making



YELLOW PIGMENTS 59

it sometimes difficult to class them properly, as they come
to the border line of each of the main groups.

Mining and Production

Volumes might be written upon this one pigment
alone without exhausting the subject matter. While
it might be attractive to a specialist in colors, much of
the matter would have but little interest to the general
reader.

Ocher is mined and obtained from the bowels of the
earth in many different ways, depending upon the depth
required to reach it, or to the topography of the
surface of the land. The price of labor and advancement
in civilization, and the consequent use of labor-saving
machinery, come in also as factors in the problem of
mining. Sometimes shafts are sunk to it in level
sections of country if the veins are deep. If, on the con-
trary, they lie near the surface, an open cut is made to
the veins, and they are simply elevated, or, better still, a
track is made and the ocher shoveled right into the car.

In the hill sections where it occurs as an outcrop above
the valleys, it is tunneled out and loaded in small cars
which are run out on a track in much the same manner
as coal under similar conditions. In many beds, seams
are found where for a few feet or inches a better grade
of ocher is found than in the rest of the vein. If it be
found to be very much better, it is shoveled out separately
and handled by itself.

In its natural state, ocher is usually mixed with many
impurities, such as roots of trees or plants, sand, gravel,
etc. For the cheaper grade, or what is known as " un-
washed " ocher, the earth after having been brought
from the mines is simply sifted through a screen and
barreled. Only the very lowest or ordinary ocher is sold



60 MODERN PIGMENTS

in that way, and the bulk of it is washed, and the very
fine qualities re washed ; but with the system of continuous
settling tanks it is seldom practiced any more, as the
very finest can be obtained from the farthest tanks.
This is equal practically to rewashing, and the method
was described under the heading of "Whiting." It is
needless to repeat it in this connection, as it is the same,
there being no difference in the operation nor its principles.

As already told, the finest is that which settles in the
tanks situated the farthest from the outpour, and the
settlings are graded accordingly as extra fine, superfine,
double washed, single washed, etc. These washings or
levigations are no index to the quality of an ocher, and
only signify the greater or lesser freedom from impurities
contained in the ocher.

There is still another method of mining ocher, which is
sometimes employed in hilly countries. A dam is built
across a valley with a sluiceway at its lowest level, through
which the water from the pound resulting from damming
the valley can be let out or kept in by shutting the gate in
the sluiceway.

After the heavy spring and early summer rains are over,
the mining commences. Hydraulic machinery is used,
and streams play upon the ocher beds in the hills adjacent
to the valley. This dissolves them and washes down the
earth into the pent-up valley below; after a sufficient
quantity has been washed out, which is gauged by the
capacity of the pond formed by the dam, it is allowed
to settle. When the water has cleared, it is allowed to
escape through the sluiceway, while the ocher remains
as a pulpy deposit. It is left in that state to dry out by
the action of the sun's rays. This requires some little
time, and in wet seasons there is considerable risk attached
to this method of mining; but there is usually nice weather



YELLOW PIGMENTS 61

in the autumn, when it is taken advantage of to handle the
ocher.

By this system the heavier impurities are deposited
long before reaching the pond, and little else than the
ochered water reaches there, as the gravel and roots are
screened out early in the runways through which the
flow is made to reach the pond. The sand settles all
along its course, or at its first entering into the pond; that
which has been held in solution until it reaches the main
part of the depositing pond being usually a fair quality of
ocher which requires no further washing for ordinary use.

When the pulp has dried sufficiently, teams are set to
work with plows and scrapers, and are loaded with the
loosened ocher earth and hauled out to the packing sheds,
which are roughly constructed affairs, but sufficiently tight
to keep the ocher from rain and consequent damage.
There it is again pulverized, screened, barreled, and placed
either in cars for shipment or in storage warehouses.

This method is by far the cheapest way of handling
ocher, but it is limited in that it cannot be made contin-
uous. It is ingenious, and might have been the invention
of a Down East Yankee, but that is not so. It is that of a
plodding Pennsylvania Dutchman; at least, he was the first
one to put the system into use in America, and possibly
in the whole world. His works are situated near Allen-
town, Pennsylvania, and are located in a small valley
through which is a runlet which gives the water a chance
to reach the larger streams, but which is usually dry
except during the heavy spring rains.

Properties and Uses

The statement was made that ochers could be grouped
into two general classes, and so they may for the purpose
of examining their characteristics and properties.



62 MODERN PIGMENTS

The two extremes are taken as types, but in reality
there are some ochers that are so near the half-way mark
between the two types, that it takes a good deal of guess-
ing to tell where they rightly belong. Besides, there are
any number of grades from the one type down toward the
dividing line forming the line of demarcation of the other.
Speaking in a general manner, the bulk of European ochers
belongs to the class of ochers containing a silicate base,
while those found so far in America are more argillaceous
or alminous in character, and may be so classed.

If the reader bears in mind what was said concerning
the silicate white earths under that heading, he will have
no trouble to understand why ochers with a silicate base
are much better than those having a clay base, at least for
the painting of surfaces exposed to the weather. He will
also understand why the clay ochers are best adapted to
distemper work.

One half of the lamentations which many painters
indulge in because of the troubles they have had, caused
by the use of ocher, and in the airing of which they at
times fill the columns of the trade papers, can be easily
traced to the use of the wrong ocher. Investigations
will always show that it was an ocher with a clay base
that was the disturbing element.

One never hears of troubles from those painters who
use the silicate-based ochers under the very same condi-
tions where the other kind is said to have gone wrong, and
these can hardly find words good enough to utter the
approval they have to give.

Both are truthful in the telling of their experiences, but
while each has to tell them from the use of a pigment
which has the same name and possibly the same color,
each is in reality speaking of something of an entirely
different nature and properties.



YELLOW PIGMENTS 63

The troubles had by those who used the clay ochers
are of the same nature as those to be expected from the
use of china clay, as has been related in the former chapter.
Clay ochers when thoroughly dry have parted with the
moisture which they originally contained. If a building
is primed with such an ocher, it may be called hermeti-
cally sealed, especially if the priming was a heavy one, as is
usually put on for cheap two-coat work. This heavy
priming has practically sealed up the wood and prevented
the penetrating of the second or finishing coat, the fine
particles of the clay and oil combining to make a poreless
glazed surface. The supervening coat put over it dries
in much the same way as it would upon a piece of glass;
it is not able to anchor itself into the non-porous priming.
If the priming had been composed of white lead alone, or
of white lead with a reasonable quantity of zinc with it,
and put on not too heavy, the priming would have been
porous. The finishing coat of lead, or lead and zinc, put
over a heavy clay ocher priming, dries upon the surface
without clinching itself to it, because it is non-porous.
This coat naturally dries thoroughly, having contact
with the atmosphere, and becomes porous after the linseed
oil has lost its glyceride. The ocher underneath is reached
through these pores by the moisture in wet weather,
which it will absorb in sufficient quantity to make
trouble. During dry, hot weather, this absorbed moisture
will be drawn out of it in the form of steam or vapor.
Much of it will escape through the same pores by which
it entered, but some may not because of a surplus of
moisture finding its way to some porous part of the wood,
and when the heat is great, the steam not being able to
escape as fast as it is formed, forms a blister under the
coat or coats applied over the clay ocher priming, and there
is trouble. This absorption and evaporation continually



64 MODERN PIGMENTS

going on tend in time to loosen the superadded coat or
coats and to make them part company from the priming,
which usually remains intact. This is one of the main
causes of complaint made against the use of ocher as a
primer.

Silicate ochers have no such effect. Silica does not
absorb water. It has no affinity for it, consequently
there can never be any of it, either by absorption or other-
wise, to escape out of it in the form of steam during
warm weather, so that there is no danger of the super-
added coats coming off it, as related of the clay ocher.
Being more porous, the finishing coat becomes anchored
to it, and if it has been properly compounded will remain
attached as long as it would upon a lead priming. It is,
of course, possible to mix a finishing coat of dope, but
such would come off of anything it was applied upon, and
this is not a matter for serious consideration.

All kinds of ochers are great absorbents of linseed oil,
and should be bought ground in oil rather than in the
dry state, unless one possesses good grinding machinery,
which is something very unusual.

As may be readily understood, the mere percentage of
strength of the colored matter (hydrate ferric oxide) con-
tained in an ocher is not always a criterion whereby to
judge of its quality or actual value. The better grades of
French ochers seldom contain as much as 25 per cent of
ferric oxide, and usually much less than that.

Every painter and decorator is pretty well acquainted
with the high character of some of the French ochers,
also with some of the English of the Oxford class. These
last are considered the best found in England, and justly so.

The following analysis is taken from Church's "Chemistry
of Paints," and was made by Professor Church himself
from a sample of ocher which was taken from the Shotover



YELLOW PIGMENTS 65

Hill mines near Oxford, and which he says represents
fairly the quality of the Oxford ochers:

Hygroscopic moisture 7.1

Combined water 9.0

Ferricoxide . ..... ......;. . 13.2

Alumina 6.3

Silica . . . -. . . 61.5

Calcium sulphate .' .. . . 1.4

Undetermined 1.5

100

The above analysis shows nearly two thirds of the com-
ponent parts of that ocher to consist of silica, therefore
one can pin his faith to it for all kinds of outdoor painting.
But note the comparatively small percentage of ferric