ON THE SECONDARY, ORANGE.
Orange is the first of the secondary colours in relation to light, being
in all the variety of its hues composed of _yellow_ and _red_. A true or
perfect orange is such a compound of red and yellow as will neutralize a
perfect blue in equal quantity either of surface or intensity; and the
proportions of such compound are five of perfect red to three of perfect
yellow. When orange inclines to red, it takes the names of _scarlet_,
_poppy_, &c.: in gold colour, &c., it leans towards yellow. Combined
with green it forms the tertiary _citrine_, and with purple the tertiary
_russet_: it also furnishes a series of warm semi-neutral colours with
black, and harmonizes in contact and variety of tints with white.
Orange is an advancing colour in painting:--in nature it is effective at
a great distance, acting powerfully on the eye, diminishing its
sensibility in accordance with the strength of the light in which it is
viewed. It is of the hue, and partakes of the vividness of sunshine, as
it likewise does of all the powers of its components, red and yellow.
Pre-eminently a _warm_ colour, being the equal contrast of or antagonist
to blue, to which the attribute of _coolness_ peculiarly belongs, it is
discordant when standing alone with yellow or with red, unresolved by
their proper contrasts or harmonizing colours, purple and green. As an
archeus or ruling colour, orange is one of the most agreeable keys in
toning a picture, from the richness and warmth of its effects. If it
predominate therein, for the colouring to be true, the violet and purple
should be more or less red, the red more or less scarlet, the yellow
more or less intense and orange, and the orange itself be intense and
vivid. Further, the greens must lose some of their blue and consequently
become yellower, the light blues be more or less light grey, and the
deep indigo more or less marrone.
Although the secondary colours are capable of being obtained by
admixture of the primaries in an infinitude of hues, tints, and shades;
yet simple original pigments of whatever class--whether secondary,
tertiary, or semi-neutral--are, it has been said before, often superior
to those compounded, both in a chemical and artistic sense. Hence a
thoroughly good original orange is only of less value and importance
than a thoroughly good original yellow, a green than a blue, or a
purple than a red. To produce pure and permanent compound hues requires
practice and knowledge, and we too often see in the works of painters
combinations neither pleasing nor stable. Colours are associated with
each other which do not mix kindly, and compounds formed of which one or
both constituents are fugitive. As a consequence, mixed tints are
frequently wanting in clearness, and, where they do not disappear
altogether, resolve themselves into some primary colour; orange becoming
red by a fading of the yellow, green yellow by a fading of the blue, and
purple blue by a fading of the red. Again, with regard to compound
tints, there is the danger of one colour reacting upon and injuring
another, as in the case of greens obtained from chrome yellow and
Prussian blue, where the former ultimately destroys the latter. Of
course a mixture of two permanent pigments which do not react on each
other will remain permanent; the green, for instance, furnished by
aureolin and native ultramarine lasting as long as the ground itself. To
produce, however, the effects desired, the artist does not always stop
to consider the fitness and stability of his colours in compounding,
even if he possess the needed acquaintance with their physical and
chemical properties. At all times, therefore, but especially when such
knowledge is slight, good orange, &c., pigments are of more or less
value, as by their use the employment of inferior mixtures is to a great
extent avoided. In mingling primary with primary, if one colour does not
compound well with the other, or is fugacious, the result is failure;
but a secondary is not so easily affected by admixture: a green, for
example, is seldom quite ruined by the injudicious addition of blue or
yellow; and even if either of the latter be fugitive, the green will
remain a green if originally durable. Thus the secondaries, if they are
not already of the colour required, may be brightened or subdued,
deepened or paled, with comparative impunity. The artist who, from long
years of experience, knows exactly the properties and capabilities of
the colours he employs, may in a measure dispense with secondary
pigments, and obtain from the primaries mixed tints at once stable,
beautiful, and pure; but even he must sometimes resort to them, as when
a green like emerald or viridian is required, which no mixture of blue
and yellow will afford. The primaries, by reason of their not being able
to be composed of other colours, occupy the first place on the palette,
and are of the first importance; but the secondaries are far too useful
to be disregarded, and have a value of their own, which both veteran and
tyro have cause to acknowledge.
The list of original orange pigments was once so deficient, that in some
old treatises on the subject of colours, they are not even mentioned.
This may have arisen, not merely from their paucity, but from the
unsettled signification of the term orange, as well as from improperly
calling these pigments reds, yellows, &c. In these days, however, orange
pigments are sufficiently numerous to merit a chapter to themselves;
they indeed comprise some of the best colours on the palette.
155. BURNT SIENNA,
or _Burnt Terra di Sienna_, is calcined raw Sienna, of a rich
transparent brown-orange or orange-russet colour, richer, deeper, and
more transparent than the raw earth. It also works and dries better, has
in other respects the qualities of its parent colour, and is a most
permanent and serviceable pigment in painting generally. For the warm
tints in rocks, mud banks, and buildings, this colour is excellent. When
mixed with blue it makes a good green; furnishing a bright green with
cobalt, and one much more intense with Prussian blue. For the foresea,
whether calm or broken by waves, it may be employed with a little
madder; while compounded with a small portion of the latter and lamp
black, it meets the hues of old posts, boats, and a variety of near
objects, as the tints may be varied by modifying the proportions of the
component colours. Used with white, it yields a range of sunny tones;
and with aureolin or French blue and aureolin will be found of service,
the last compound giving a fine olive green. Similar but fugitive greens
are afforded by admixture of burnt Sienna with indigo and yellow or
Roman ochre, or raw Sienna; tints which may be saddened into olive
neutrals by the addition of sepia, and rendered more durable by
substituting for indigo Prussian blue and black. Mixed with viridian, it
furnishes autumnal hues of the utmost richness, beauty, and permanence;
and, alone, is valuable as a glaze over foliage and herbage. For the
dark markings and divisions of stones a compound of Payne's gray and
burnt Sienna will prove serviceable; while for red sails the Sienna,
either by itself, with brown madder, or with Indian red, cannot be
surpassed. For foregrounds, banks and roads, cattle and animals in
general, burnt Sienna is equally eligible, both alone and compounded. It
has a slight tendency to darken by time.
156. CADMIUM ORANGE
was first introduced to the art-world at the International Exhibition of
1862, where it was universally admired for its extreme brilliancy and
beauty, a brilliancy equalled by few of the colours with which it was
associated, and a beauty devoid of coarseness. We remember well the
power it possessed of attracting the eye from a distance; and how, on
near approach, it threw nearly all other pigments into the shade. It has
in truth a lustrous luminosity not often to be met with, added to a
total absence of rankness or harshness. A simple original colour,
containing no base but cadmium, it is of perfect permanence, being
uninjured by exposure to light, air or damp, by sulphuretted hydrogen,
or by admixture. Having in common with cadmium sulphides a certain
amount of transparency, it is invaluable for gorgeous sunsets and the
like, either alone or compounded with aureolin. Of great depth and power
in its full touches, the pale washes are marked by that clearness and
delicacy which are so essential in painting skies. As day declines, and
blue melts into green, green into orange, and orange into purple, the
proper use of this pigment will produce effects both glowing and
transparent. Transparency signifies the quality of being seen through or
into; and in no better way can it be arrived at than by giving a number
of thin washes of determined character, each lighter than the preceding
one. With due care in preserving their forms, from the commencement to
the termination, such washes of orange will furnish hues the softest and
most aerial. For bits of bright drapery, a glaze over autumn leaves, and
mural decoration, this colour is adapted; while in illumination it
supplies a want formerly much felt. "With the exception of scarlet or
bright orange," said Mr. Bradley, nine or ten years since, in his Manual
of Illumination, "our colours are everything we could wish." As an
original pigment, a permanent scarlet does not yet exist; but the
brilliancy of cadmium orange cannot be disputed, nor its claim to be the
only unexceptionable bright orange known. It even assists the formation
of the other colour: remarks the author mentioned, "Brilliancy is
obtained by gradation. Suppose a scarlet over-curling leaf, for example.
The whole should be painted in pure orange, with the gentlest possible
after-touch of vermilion towards the corner under the curl. When dry, a
firm line--not wash--of carmine, (of madder, preferable.--_Ed._), passed
within the outline on the shade side only of the leaf, will give to the
whole the look of a bright scarlet surface, but with an indescribable
superadded charm, that no merely flat colour can possess." In the same
branch of art, illumination, cadmium orange, opposed to viridian,
presents a most dazzling contrast, especially if relieved by purple.
157. CHINESE ORANGE
belongs to the coal-tar colours, and ought strictly to have been classed
therewith. We have preferred, however, to keep it separate, because, as
Chinese Orange, it was introduced as a pigment, and has not been
employed as a dye. In colour, it somewhat resembles burnt Sienna,
enriched, reddened, brightened, and made more transparent, by admixture
with crimson lake. From its behaviour, it would seem to be composed of
yellow and red, such a compound as magenta and aniline yellow would
afford. Its pale washes are uncertain, being apt to resolve themselves
into red and yellow, of which the latter appears the most permanent;
for, on exposure to light and air, the red more or less flies, leaving
here a yellow, and there a reddish-yellow ground: in places both red and
yellow disappear. Like all fugitive colours, it is comparatively stable
when used in body; but even then it entirely loses its depth and
richness, and in a great measure its redness, becoming faded and
yellowish. In thin washes or glazing it is totally inadmissible; and,
being neither a red, an orange, nor a brown, is unsuited to pure
effects. Nevertheless, where it need not be unduly exposed; in portfolio
illuminations, for instance, the richness, subdued brilliancy, and
transparency of this pigment, justify its adoption. It is not affected
by an impure atmosphere.
Aniline colours may be adapted for oil painting by dissolving them in
the strongest alcohol, saturating the solution with Dammar resin,
filtering the tincture, and pouring the filtrate either on pure water or
solution of common salt, stirring well all the time. The water or brine
solution must be at least twenty times the bulk of the tincture. The
colour after being collected on a filter, washed, and dried, can be
ground with linseed oil, poppy oil, or oil varnishes.
158. CHROME ORANGE,
_Orange Chrome_, or _Orange Chromate of Lead_, is a sub-chromate of lead
of an orange-yellow colour, produced by the action of an alkali on
chrome yellow. Like all the chromates of lead, it is characterized by
power and brilliancy; but also by a rankness of tone, a want of
permanence, and a tendency to injure organic pigments. By reason of its
lead base it is subject to alteration by impure air, but is on the whole
preferable to the chrome yellows, being liable in a somewhat less degree
to their changes and affinities. As, however, a colour has no business
to be used if a better can be procured, the recent introduction of
cadmium orange renders all risk unnecessary.
159. MARS ORANGE,
_Orange de Mars_, is a subdued orange of the burnt Sienna class, but
without the brown tinge that distinguishes the latter. Marked by a
special clearness and purity of tone, with much transparency, it affords
bright sunny tints in its pale washes, and combines effectively with
white. Being an artificial iron ochre it is more chemically active than
native ochres, and needs to be cautiously employed with pigments
affected by iron, such as the lakes of cochineal and intense blue.
160. MIXED ORANGE.
Orange being a compound colour, the place of original orange pigments
can be supplied by mixtures of yellow and red; either by glazing one
over the other, by stippling, or by other modes of breaking and
intermixing them, according to the nature of the work and the effect
required. For reasons lately given, mixed pigments are apt to be
inferior to the simple or homogeneous both in colour, working, and other
properties; yet some pigments mix and combine more cordially and with
better results than others; as is the case with liquid rubiate and
gamboge. Generally speaking, the compounding of colours is easier in oil
than in water; but in both vehicles trouble will be saved by beginning
with the predominating colour, and adding the other or others to it.
Perhaps in this, our first chapter on the secondary colours, and
consequently on colours that can be compounded, a few remarks on mixed
tints from a chemical point of view will not be deemed superfluous.
There are two ways, we take it, of looking at a picture--from a purely
chemical, and from a purely artistic, point of view. Regarded in the
first light, it matters little whether a painting be a work of genius or
a daub, provided the pigments employed on it are good and properly
compounded. The effects produced are lost sight of in a consideration of
the materials, their permanence, fugacity, and conduct towards each
other. Painting is essentially a chemical operation: with his pigments
for reagents, the artist unwittingly performs reaction after reaction,
not with the immediate results indeed of the chemist in his laboratory,
but often as surely. As colour is added to colour, and mixture to
mixture, acid meets alkali, metal animal, mineral vegetable, inorganic
organic. With so close a union of opposite and opposing elements, the
wonder is not so much that pictures sometimes perish, but that they ever
live. It behoves the artist, then, not only to procure the best and most
permanent pigments possible, but to compound them in such a manner that
his mixed tints may be durable as well as beautiful. To effect or aid in
effecting this, although he may not always be able to act upon them, the
following axioms should be borne in mind:--
1. If they do not react on each other, a permanent pigment added to a
permanent pigment yields a permanent mixture.
2. If they do react on each other, a permanent pigment added to a
permanent pigment yields a semi-stable or fugitive mixture.
3. A permanent pigment added to a semi-stable pigment yields a
semi-stable mixture.
4. A permanent pigment added to a fugitive pigment yields a fugitive
mixture.
Consequently--
5. A permanent pigment may be rendered fugitive or semi-stable by
improper compounding.
6. A semi-stable or fugitive pigment is not rendered durable by being
compounded.
7. As a chain is only as strong as its weakest link, so a mixture is
only as permanent as its least durable constituent.
To give illustrations--
1. Ultramarine added to Chinese white yields a permanent mixture.
2. Ultramarine added to an acid constant white yields a semi-stable or
fugitive mixture.
3. Ultramarine added to Prussian blue yields a semi-stable mixture.
4. Ultramarine added to indigo yields a fugitive mixture.
Except in the second instance, where the blue is either partially or
wholly destroyed--in time, be it remembered, not at once--according to
the quantity and strength of the acid in the white, the ultramarine
remains unchanged. Hence at first sight our third and fourth conclusions
may appear wrong; inasmuch as, it may be argued, a blue mixture cannot
be semi-stable or fugitive when blue is left. To this we reply, unless
both constituents are fugitive, a mixture will always more or less
possess colour; but, if even one constituent be semi-stable or fugitive,
a mixture will slowly but surely lose _the_ colour for which it was
compounded, and be _as a mixture_ semi-stable or fugitive.
It need hardly be observed that the number of permanent orange, green,
and purple hues which the artist can compound, depends mainly on the
number of permanent yellows, reds, and blues at his disposal. In mixed
orange, therefore, a selection of durable yellows and reds is of the
first importance. It should, however, be remarked that mixed orange,
more sober and less decided, is obtainable by the use of citrine and
russet; in the former of which yellow predominates, and in the latter,
red: consequently orange results when yellow is added to russet, red to
citrine, or citrine to russet.
PERMANENT YELLOWS. | PERMANENT REDS.
|
Aureolin. | Cadmium Red.
Cadmium, deep. | Liquid Rubiate.
Cadmium, pale. | Madder Carmine.
Lemon Yellow. | Rose Madder.
Mars Yellow. | Mars Red.
Naples Yellow, modern. | Ochres.
Ochres. | Vermilions.
Orient Yellow. |
Raw Sienna. |
None of these pigments react on each other, and from them can be
produced the most durable mixed orange that yellow and red will afford.
161. NEUTRAL ORANGE,
or _Penley's Neutral Orange_, is a permanent compound pigment composed
of yellow ochre and the russet-marrone known as brown madder: it is
chiefly valuable in water-colour. Paper, being white, is too opaque to
paint upon, without some wash of colour being first passed over it;
otherwise the light tones of the sky are apt to look crude and harsh. It
must, therefore, be gone over with some desirable tint, that shall
break, in a slight degree, the extreme brilliancy of the mere paper. For
this purpose, a thin wash of the orange is to be put over the whole
surface of the paper with a large flat brush, care being taken never to
drive the colour too bare, _i.e._ never to empty the brush too closely,
but always to replenish before more is actually required. This first
wash of colour not only gives a tone to the paper, but secures the
pencil sketch from being rubbed out.
The reason why, in this compound, yellow ochre, as a yellow, is
preferred to any of the others, is, that it is a broken yellow, that is,
a yellow slightly altered by having another hue, such as red, or brown,
in its composition. It is somewhat opaque too, and hence, from this
quality, is especially adapted for distances. Brown madder also is a
subdued red, which, when in combination with the former, produces a
neutral orange, partaking of the character of soft light. As a general
rule, yellow ochre is to predominate in broad daylight, and brown madder
in that which is more sombre and imperfect: hence the pigment can be
yellowed or reddened, by the addition of one or the other. For a clear
sunset, the neutral orange must be repeated, with a preponderance of
ochre at the top, assisted by a little cadmium yellow near the sun; the
madder being added downwards.
In treating of distant mountains, a distinction is to be made between
them and the clouds, the former requiring solidity, while the latter are
only to be regarded as vapour and air. Mountains, being opaque bodies,
are acted upon by atmosphere more or less, according to their position,
their distance, and the state of the weather. To express this
distinction, recourse must be had to an under tint, except where the
tone is decidedly blue--an uncommon case. No mixture can give this with
such truth as the neutral orange. A wash, therefore, should be passed
over the mountains, with nearly all yellow in the high lights, or in the
gleams of sunshine, and, on the contrary, almost all brown madder for
the shadows. These two degrees of tone must be run into each other
while the drawing is wet. A beautiful and soft under tone will thus be
given to receive the greys.
162. ORANGE, OR BURNT ROMAN OCHRE,
called also _Spanish Ochre_, is a very bright yellow or Roman ochre
burnt, by which operation it acquires warmth, colour, transparency, and
depth. Moderately bright, it forms good flesh tints with white, dries
and works well both in water and oil, and is a very good and eligible
pigment. It may be used in enamel painting, and has all the properties
of its original ochre in other respects.
A redder hue is imparted by mixing the ochre with powdered nitre before
ignition, the orange red being subsequently washed with hot water.
* * * * *
163. _Anotta_,
Annotto, Annatto, Arnotto, Arnotta, Terra Orellana, Rocou, &c., is met
with in commerce under the names of cake anotta, and flag or roll
anotta. The former, which comes almost exclusively from Cayenne, should
be of a bright yellow colour: the latter, which is imported from the
Brazils, is brown outside and red within. It is prepared from the pods
of the _bixa orellana_, and appears generally to contain two colouring
matters, a yellow and a red, which are apt to adhere to each other and
produce orange. Anotta dissolves with difficulty in water, but readily
in alcohol and alkaline solutions, from which last it may be thrown down
as a lake by means of alum. Being, however, exceedingly fugitive and
changeable, it is not fit for painting; but is chiefly employed in
dyeing silk, and colouring varnishes and cheese. Very red cheese should
be looked upon with suspicion, for although the admixture of anotta is
in no way detrimental to health provided the drug be pure, it is
commonly adulterated with red lead and ochre. Several instances are on
record that Gloucester and other cheeses have been found contaminated
with red lead, through having been coloured with anotta containing it,
and that this contamination has produced serious consequences.
_Bixine_ is a purified extract of anotta made in France, and used by
dyers.
164. _Antimony Orange_,
Golden Sulphur of Antimony, or Golden Yellow, is a hydro-sulphuret of
antimony of an orange colour, which is destroyed by the action of strong
light. It is a bad dryer in oil, injurious to many pigments, and in no
respect eligible either in water or oil.
165. _Chromate of Mercury_
has been improperly classed as a red with vermilion, for though it is of
a bright ochrous red in powder, when ground it becomes a bright
ochre-orange, and affords with white very pure orange tints.
Nevertheless it is a bad pigment, since light soon changes it to a deep
russet colour, and foul air reduces it to extreme blackness.
166. _Damonico_,
or Monicon, is an iron ochre, being a compound of raw Sienna and Roman
ochre burnt, and having all their qualities. It is rather more russet in
hue than the pigment known as orange or burnt Roman ochre, has
considerable transparency, is rich and durable in colour, and furnishes
good flesh tints. As in orange ochre, powdered nitre may be employed in
its preparation. Notwithstanding its merits, it is obsolete or nearly
so; doubtless because burnt Sienna mixed with burnt Roman ochre
sufficiently answers the purpose.
167. _Gamboge Orange._
On adding acetate of lead to a potash solution of gamboge, a rich bright
orange is precipitated, which may be washed on a filter till the
washings are colourless, and preserves its hue with careful drying. The
orange which we thus obtained stood well in a book, but it cannot be
recommended as an artistic pigment. Perhaps in dyeing, the lead and
gamboge solutions might be worth a trial.
168. _Laque Minérale_
is a French pigment, a species of chromic orange, similar to the orange
chromate of lead. This name is likewise given to orange oxide of iron.
169. _Madder Orange_,
or Orange Lake. It has been said that the yellows so-called produced
from madder are not remarkable for stability, differing therein from the
reds, purples, russets, and browns. Like them, this 'orange' is of
doubtful colour and permanence, and not to be met with, brilliant and
pure, on the palette of to-day. The russet known as Rubens' madder has a
tendency to orange.
170. _Orange Lead_,
of a dull orange colour, is an orange protoxide of lead or massicot.
Like litharge, it may be employed in the preparation of drying oils,
and, being a better drier than white lead, may be substituted for it in
mixing with pigments which need a siccative, as the bituminous earths.
Minium sometimes leans to orange; and there is made from ceruse a
peculiar red, _Mineral Orange_.
_Orange Orpiment_,
or Realgar, has also been called Red Orpiment, improperly, since it is
a brilliant orange, inclining to yellow. There are two kinds, a native
and an artificial, of which the former is the _sandarac_ of the
ancients, and is rather redder than the latter. They possess the same
qualities as pigments, and as such resemble yellow orpiment, to which
the old painters gave the orange hue by heat, naming it alchemy and
burnt orpiment. Orange orpiment contains more arsenic and less sulphur
than the yellow, and is of course highly poisonous. It is often
sophisticated with brickdust and yellow ochre.
172. _Thallium Orange_
is produced when bichromate of potash is added to a neutral salt of the
protoxide of thallium, as an orange-yellow precipitate. The scarcity of
the metal precludes their present introduction as pigments, but if the
chromates of thallium were found to resist the action of light and air,
and not to become green by deoxidation of the chromic acid, they might
possibly prove fitted for the palette. It is a question whether their
_very_ slight solubility in water would be a fatal objection; and,
although they would be liable to suffer from a foul atmosphere, we are
inclined to think the effects would not be so lasting as in the
chromates of lead. Like lead sulphide, the sulphide of thallium ranges
from brown to brownish-black, or grey-black; and, like it too, is
subject to oxidation and consequent conversion into colourless sulphate.
It is, however, much more readily oxidized than sulphate of lead; and
hence the thallium chromates would doubtless soon regain their former
hue on exposure to a strong light.
Mr. Crookes, who discovered this new metal in 1861, believes that the
deep orange shade observable in some specimens of sulphide of cadmium is
due to the presence of thallium. He has frequently found it, he says, in
the dark-coloured varieties, and considers the variations of colour in
cadmium sulphide to be owing to traces of thallium. That thallium
affects the colour is most probable, but it is not necessarily the cause
of the orange hue. The tint of cadmium sulphide is a mere matter of
manufacture, seeing that from the same sample of metal there can be
obtained lemon-yellow, pale yellow, deep yellow, orange-yellow, and
orange-red. With deference to the opinion of a chemist so distinguished,
we hold that thallium rather impairs the beauty of cadmium sulphide than
imparts to it an orange shade, the thallium being likewise in the form
of sulphide, and therefore more or less black. On chromate of cadmium,
made with bichromate of potash, thallium would naturally confer an
orange hue.
173. _Uranium Orange_
is obtainable by wet and dry methods as a yellowish-red, or, when
reduced to powder, an orange-yellow, uranate of baryta. It is an
expensive preparation, superfluous as a pigment.
174. _Zinc Orange._
When hydrochloric acid and zinc are made to act on nitro-prusside of
sodium, a corresponding zinc compound is formed of a deep orange colour,
slightly soluble in water, and not permanent.
* * * * *
For a secondary colour, orange is well represented on the modern
palette, and can point to some pigments as good and durable as any to be
found among the primaries. Burnt Sienna, cadmium orange, Mars orange,
neutral orange, and orange or burnt Roman ochre, are all strictly
permanent. The so-called orange vermilions were, it will be remembered,
classed among the reds.
As semi-stable, must be ranked chrome orange; and as fugitive, Chinese
orange, orange orpiment, and orange lead.
From the foregoing division, the predominance of eligible orange
pigments over those less trustworthy is manifest. Unfortunately, with
many painters it is not so manifest that their secondary and compound
colours should receive as much attention as the primaries, and that it
is their duty, not only to the art which they practice, but to the
patrons for whom they practice it, that their orange and green and
purple hues, should be as durable as their yellows, reds, and blues. For
such, the introduction of a new permanent pigment is of little interest,
unless its colour be primary; so wedded are they to that passion for
compounding which the chemist views with dismay. With dismay, because he
knows that the rules of mixture are severe, and cannot with impunity be
altered; that, although disguised in oil or gum, each pigment is a
chemical compound, with more or less of affinity and power, more or less
likely to act or be acted upon. Because he knows that, except with the
most experienced artists, compounding leads to confusion; and that in it
the temptations to use semi-stable or fugitive colours are strong. Look
at those tables of mixed tints of which artist-authors are so fond, and
tell us whether they always bear scrutiny--surely not. Admirable,
perfect as these tints may be in an artistic sense, how often is their
beauty like the hectic flush of consumption, which carries with it the
seeds of a certain death. Will that orange where Indian yellow figures
ever see old age, or that green with indigo, or purple with cochineal
lake? Will they not rather spread over the picture the Upas-tree of
fugacity, and kill it as they die themselves!