ON THE PRIMARY, YELLOW.
Yellow is the first of the primary or simple colours, nearest in
relation to, and partaking most of the nature of, the neutral white; it
is accordingly a most advancing colour, of great power in reflecting
light. Compounded with the primary _red_, it constitutes the secondary
_orange_, as well as its relatives, scarlet, and other warm colours.
It is the archeus, or prime colour, of the tertiary _citrine_;
characterises in like manner the endless number of semi-neutral colours
called _brown_, and enters largely into the complex hues termed buff,
bay, tawny, tan, dan, dun, drab, chestnut, roan, sorrel, hazel, auburn,
isabela, fawn, feuillemort, &c. Yellow is naturally associated with red
in transient and prismatic colours, and is the principal power with it
in representing the effects of warmth, heat, and fire. Combined with the
primary _blue_, yellow furnishes all the variety of the secondary
_green_, as well as, subordinately, the tertiaries _russet_ and _olive_.
It also enters in a very subdued degree into cool, semi-neutral, and
broken colours, and assists in minor proportion with blue and red in the
composition of _black_.
As a pigment, yellow is a tender delicate colour, easily defiled, when
pure, by other colours. In painting it diminishes the power of the eye
by its action in a strong light, at the same time becoming less distinct
as a colour; while, on the contrary, it assists vision and becomes more
distinct as a colour in a neutral somewhat declining light. These powers
of colours upon vision require the particular attention of the
colourist. To remedy the ill effect arising from the eyes having dwelt
upon a colour, they should be either passed gradually to its opposite
colour, and refreshed amid compound or neutral tints, or washed in the
clear light of day. Hence, in viewing large collections of pictures,
their colours will be more duly estimated by sometimes walking to the
window, or by taking an occasional glance at a millboard, which may be
carried in the hand, painted a cool gray.
In a warm light, yellow becomes totally lost, but is less diminished
than all other colours, except white, by distance. The stronger tones of
any colour subdue its fainter hues in the same proportion as opposite
colours and contrasts exalt them. The contrasting colours of yellow are
a purple inclining to blue when the yellow leans to orange, and a purple
inclining to red when the yellow tends to green, in the mean
proportions of _thirteen_ purple to _three_ yellow, measured in surface
or intensity. Being nearest to the neutral white in the natural scale of
colours, yellow accords with it in conjunction; while, of all colours,
except white, it contrasts black most powerfully. Yellow is discordant
when standing alone with orange, unsupported by other colours.
On account of the paucity of fine yellows among the ancients, we find
that in many paintings and beautiful illuminated MSS. of old, glowing
with vermilion and ultramarine, the place of yellow was supplied by
gilding. Now, certainly, no such scarcity exists; of the three primary
colours, good yellows being the most numerous. It may be observed of
yellow pigments that their colour being primary and therefore simple,
they cannot be composed by any mixture of other colours. The same remark
of course applies to pigments which are red or blue.
20. AUREOLIN.
In these days a new pigment soon finds its level, standing or falling
according to its merits. There are too many colours already on the
palette for a fresh comer to have much chance, unless it possess some
great distinguishing quality, or can take a place which has never been
occupied. Such a void aureolin fills. This "magnificent yellow
pigment," says the _Chemical News_, "supplies a desideratum hitherto in
vain sought for by artists. It is the nearest approach to a perfect
yellow in existence, and more closely resembles the purity of the
prismatic spectrum than any other artificial colour. It is transparent,
has great brilliancy and richness, both pure and in combination, and is
very permanent, being entirely unaffected by exposure to sulphuretted
hydrogen and other atmospheric impurities, or to the direct rays of the
sun during an entire summer. Aureolin, with ultramarine and madder red,
completes the triad of brilliant, permanent, and transparent primitive
colours." The above only tallies with the statements of several
scientific chemists and artists of note, statements which a prolonged
personal experience of the colour enables us to endorse. To our
knowledge, aureolin is quite uninjured by the severest tests to which a
pigment can be subjected. We have found it bear with impunity, even in
its lightest and faintest tints, the foulest gas and the brightest
sunshine. Damp has no effect upon it; and in oil, water, or fresco, it
is equally eligible. With all other colours aureolin mixes safely and
readily, forming combinations of the utmost variety and value. It
affords beautiful transparent tints, well defined, and of exceeding
purity; the paler washes being at once clear and delicate, and admitting
the most subtle gradations of tone. The artistic properties of
aureolin, however, will be best described by quoting the following
extract from Mr. Aaron Penley's _English School of Painting in Water
Colours_:--
"I have fully tested the qualifications of _Aureolin_ for the
Landscape Painter, and, without hesitation, pronounce it to be
the most valuable addition to the 'colour box' since the
introduction of Rose Madder. It has supplied a deficiency of a
very important character. Hitherto, no Primitive Yellow has been
quite satisfactory as to its persistence; so that the Aureolin
will not only be regarded by the _artist_ as a great boon in the
production of his works, but it must also be considered as a
_real_ and _lasting benefit_ to pictorial art in general. The
permanence and unaltered purity of its lightest and faintest
tints we are assured may be confidently relied upon, inasmuch as
they have been fully established by the most severe tests to
which colour can be subjected, by several of our ablest and most
talented chemists. It is, therefore, needless to enlarge upon
its merits, other than that I, for one, feel grateful for its
introduction. Its uses are manifold, and may be considered
available for every purpose requiring a Yellow of its character.
As to Gray--perhaps it is not possible to obtain more delicately
pure and transparent aërial tints than are to be produced from
a combination of Cobalt, Rose Madder and Aureolin; all of which
are of a light description and well suited for the
representation of soft and thin effects of the atmosphere. These
colours are each of them beautiful, and yield a most exquisite
range of tones, which, as they mix together most kindly, render
them desirable where purity and delicacy are sought. As to
Foliage.--In speaking of Aureolin as adapted for the colouring
of foliage and herbage, it is impossible to say too much in its
praise. It imparts the vividness and freshness of nature to
every colour with which it is combined--a quality of the highest
order. As a colour for drapery it has no equal, and may be
employed with perfect success, either by itself or with any of
the other pigments.
"The following table of compound tints will be found extremely
useful:--
Aureolin. | Aureolin. | Aureolin. | Aureolin.
Burnt Sienna. | Vandyke Brown. | Sepia. | Sepia, or Rose
Indigo, or | Indigo, or French | | Madder.
French Blue.| Blue. | | Cobalt.
Aureolin. | Aureolin. | Aureolin. | Aureolin.
Indigo. | Oxide of Chromium.| Emerald | Light Red.
| | Green. | Cobalt, or
| | | Indigo.
Aureolin. | Aureolin. | Aureolin. | Aureolin.
Burnt Sienna. | Burnt Umber. | Brown Madder.| Rose Madder.
"Aureolin, in combination with Cobalt and Sepia, or Rose Madder,
gives most agreeable and delicate tints for distant trees, when
under the influence of a soft light, or hazy state of the
atmosphere. Having most impartially and diligently tested the
qualities of the Aureolin, I can and do most conscientiously
recommend its adoption by all who practise water-colour
painting."
The foregoing sufficiently proves the value of aureolin in water, and
similar flattering notices have been given of the colour in oil. Both in
a chemical and artistic sense, therefore, this new primitive yellow
merits the highest regard, and justly claims a foremost place among that
little band of pigments which are without fear and without reproach.
For mural decoration, aureolin is admirably adapted, but it cannot be
used in enamel, the colour being destroyed by great heat.
CADMIUM YELLOWS.
Of these there are three tints, _Deep_, a so-called _Pale_, and _Lemon_.
21. DEEP CADMIUM.
Cadmium Yellow is comparatively a recent introduction, the metal itself
not having been discovered till 1818. The cadmium yellows of commerce
are (the chromate excepted) all sulphides, and therefore not affected by
impure air. Until lately, they were not manufactured in England but
imported from abroad, and as a rule were sadly doctored. We have found
in them a large proportion of orpiment, chromate of lead, &c., together
with quantities of soluble salt, extracted by boiling water. Owing to
careless preparation, there was also present an unnecessary amount of
dirt, which interfered as much with the purity of the colour, as
sophistication lessened its stability. For these reasons, doubtless,
cadmium yellows got to be regarded by some with disfavour and suspicion;
and it may fairly be said that they did not attain their present
popularity, until they became an article of home produce.
Deep cadmium yellow, if genuine, may without hesitation be declared
permanent, both with respect to foul gas, and exposure to light or air.
The variety under notice is of extreme depth, inclining to orange,
glowing, lustrous, and brilliant. It is not very transparent, but
wonderfully clear and bright, of great power, and the most richly toned
yellow known. For draperies it is particularly adapted, and for gorgeous
sunsets is invaluable. It works and washes well, readily throws all
other yellows into the shade when used alone, and combines admirably
with Chinese white for the light touches of bright clouds or mountains.
By admixture with white, cadmium gives a series of beautiful clear
tints. When compounded with white lead, however, the colour has been
stated to be destroyed. Theoretically, this might very well happen.
Cadmium yellow is composed of cadmium and sulphur--white lead of lead
and carbonic acid. If the former parted with some of its sulphur to the
latter, sulphide of lead would result, which is black. Hence, the partly
decomposed yellow and white would be mixed with black, and there would
be formed a blackish-yellow or a yellowish-black. Again, if the cadmium
parted with the whole of its sulphur to the lead, receiving in exchange
the carbonic acid of the latter, a mixture of black sulphide of lead
with white carbonate of cadmium would be furnished, the result being a
grey. Perhaps the following rough diagram may serve to make our meaning
plainer:--
Cadmium Yellow {Cadmium. __________ Carbonate of Cadmium (White.)
{Sulphur. /
\ /
\ /
\ /
\ /
\ /
\/
/\
____/__\
White Lead {Lead. / Sulphide of Lead (Black.)
{Carbonic Acid.
Such is the theory of the reaction which might take place, but which, as
far as our own experience goes, does not. Some deep cadmium yellow which
we ourselves prepared was intimately mixed and ground with an equal
quantity by weight of Cremnitz white, and an oil rub of the compound
laid upon a tile. Having placed the latter on a shelf in the laboratory,
we watched from week to week to see if any approach to blackness
occurred, any diminution in the beauty of the tint; but could perceive
none. Hence, while admitting the possibility of the colour being
damaged or destroyed in the case of an inferior and spurious article, we
conclude that an unadulterated cadmium yellow, containing no free
sulphur, neither injures, nor is injured by, white lead, and may safely
be used therewith. At the same time, the artist should be warned to
satisfy himself of the genuineness of his pigment, or otherwise to
employ the white of zinc, at least as a medium of intervention.
A good sample of cadmium yellow may rather advantageously than otherwise
be compounded with white lead, for we have found that a mixture of equal
parts by weight of the two will bear an atmosphere of sulphuretted
hydrogen that completely blackens the white alone.
With all the sulphides of cadmium a steel palette knife is best avoided.
22. PALE CADMIUM.
The cadmium yellow so-called, is not strictly pale, but pale only when
compared with the preceding. It is, in fact, a full rich colour,
brilliant and permanent, but without that tendency to orange which
distinguishes the deep. For some purposes, when a warm tone is not
required, such a tint is preferable. In water, especially, where
delicacy of colouring can be carried to a greater degree of refinement
than in oil, these differences of hue are important. In the first
medium the faint washes show with a clearness which is not so apparent
in the last, and the most subtle gradation of tone tells with a force in
some measure lost in oil. As a consequence, the colour of the lightest
tints in the distance must be as true as that of the deepest shades in
the foreground, and hence the warmth or coldness of the pale washes of a
pigment should be duly considered.
Pale cadmium yellow with or without aureolin, is adapted for golden
sunsets, and yields with French blue a beautiful sea-green.
24. LEMON CADMIUM.
Very pale cadmium yellows are not permanent, and lemon cadmiums are
decidedly fugitive. Being, like the deep and 'pale' varieties,
sulphides, they are of course unaltered by sulphurous gas; but they will
not stand exposure to light and air, or even to light alone. Some which
were submitted in an air-tight bottle to the action of light gradually
whitened next the glass. Yet they were almost identical in composition
with the deepest and most orange hues, and might have reasonably been
presumed stable. Repeated experiments, however, both with samples of our
own making and of others' manufacture, have shown that for a cadmium to
be durable, it must be of a full, rich, comparatively deep yellow; and
that any paler product than the 'pale' alluded to cannot be depended
on. It is true that a light or lemon tint will fade quicker in water
than in oil, but a colour which is fugitive in the one vehicle cannot be
regarded as eligible in the other. From a somewhat long acquaintance
with cadmiums, we have derived the opinion that their stability rests
much on the mode of preparation, and that an amount of heat is needed
sufficient to make the sulphur _bite into_ the base. This opinion,
indeed, extends to all metallic sulphides, and our belief is, that if
vermilions were made generally by wet processes, they would not be found
the permanent pigments they undoubtedly are.
25. MUTRIE YELLOW.
Under this name a lemon sulphide of cadmium has lately appeared, to
which the foregoing remarks are applicable. A water colour rub on
exposure to air and light faded rapidly, no trace of yellow remaining in
the pale wash. The sample which came under our notice contained a
quantity of free sulphur.
It is to be regretted that these lemon cadmiums are fugacious, so
bright, so clear, are they, and of so pure a lemon tint can they be
obtained. But as no beauty of colour compensates for want of durability,
their place should be supplied by lemon yellow proper, or chromate of
baryta.
26. CHROME YELLOWS,
Also called _Jaune Minérale_, _Jaune de Cologne_ or _Cologne Yellow_,
_Pale Chrome_, and _Deep Chrome_, are chromates of lead, in which the
latter metal more or less exists, according to the paleness or depth of
the colour. Of modern introduction, they are distinguished for their
brilliancy, their opacity and body, and their going cordially into tint
with white, both in water and oil. Owing, however, to a harshness and
hardness of tone for which they are peculiar, a coarse and disagreeable
effect is apt to be produced by their use. In general, they do not
accord with the modest hues of nature, nor harmonize well with the
softer beauty of other colours. Rivalling the cadmiums in brightness,
they are wanting in the mellow richness which belongs to the deeper
varieties of those pigments, as well as in their permanency. Although
they resist the sun's rays for a lengthened period, after some time they
lose their original hue, whether employed alone or in tint, and may even
become black in impure air. Upon several pigments they produce serious
changes, ultimately destroying Prussian and Antwerp blues, when
compounded therewith in the composition of greens, &c. Ranging from
lemon to deep yellow, in oil, provided the atmosphere be good, the
chromes may be found comparatively durable; but, on the whole, the
artist cannot trust to them his reputation as a colourist.
The chromates are often mixed with sulphate of lead, as well as with the
sulphates of baryta and lime. The presence of the first is especially
objectionable, as increasing the tendency of the yellows to be blackened
by foul gas. The sulphates of baryta and lime, however, are sometimes
formed in the process of preparation, in which case they are rather an
advantage than otherwise; inasmuch as they not only lend a softness to
the colour, but decrease the proportion of leaden base, and consequently
the tendency referred to. We may remark, indeed, with respect to
pigments, that it is difficult in many instances to say where
manufacture ends and adulteration begins. A substance may be present
which, although not absolutely essential to the colour itself, has been
legitimately employed to impart a desired quality, or a certain tint.
27. COLOGNE YELLOW
Is a cheap inferior chrome yellow, unfit for artistic purposes, and
consists of twenty-five parts of chromate of lead, fifteen of sulphate
of lead, and sixty of sulphate of lime.
28. JAUNE MINERALE
Is prepared in Paris, and differs in no essential particular from
ordinary chromate of lead, except in the paleness of its colour. The
chrome yellows have also obtained other names from places or persons,
whence they have been brought or by whom they have been made. Another
lead yellow, not a chromate, has likewise been called jaune minérale.
29. CITRON YELLOW
Is chromate of zinc, a bright pale lemon-like yellow, slightly soluble
in water. It is not affected by foul gas, but does not preserve its
colour on exposure to light and air, or even when kept in a book. In
contact with organic substances it is apt to turn green. Compounded,
especially for foliage tints, this yellow is eligible; but if purity of
hue be desired, it should certainly not be employed alone. In this
chromate, as in many others, the affinity of the chromic acid to the
base is small; the former is liable to separate from the latter, and, by
deoxidation, to become converted into green oxide of chromium.
30. GALLSTONE
Is a deep-toned gorgeous yellow, affording richer tints than most other
yellows, but it cannot be depended on for permanency, and therefore is
seldom employed. Its colour is soon changed and destroyed by strong
light, though not subject to alteration by impure air. In oil it is
ineligible. A true gallstone is an animal calculus formed in the
gall-bladder, chiefly of oxen; but the pigment sold under that name is
often replaced by a substitute, resembling the original in colour, but
of greater stability.
31. GAMBOGE,
Sometimes designated _Drop Gum_, and variously written _Gamboge_,
_Camboge_, _Gamboage_, _Cambogia_, _Cambadium_, _Cambogium_,
_Gambodium_, _Gambogium_, &c., is the produce of several kinds of trees.
The natives of the coast of Coromandel call the tree from which it is
principally obtained Gokathu, which grows also in Ceylon and Siam. From
the wounded leaves and young shoots the gamboge is collected in a liquid
state and dried. Our indigenous herb Celandine yields abundantly, in the
same manner, a beautiful yellow juice of the same properties as gamboge.
Gamboge is of a gum-resinous nature and clear yellow colour. It is
bright and transparent, but not of great depth, and in its deepest
touches shines too much and verges upon brown. When properly used, it is
more durable than generally reputed, both in water and oil; and
conduces, when mixed with other colours, to their stability and keeping
their place, on account of its gum and resin. It is deepened in some
degree by ammoniacal and impure air, and somewhat weakened, but not
easily discoloured, by the action of light. Time effects less change on
this colour than on other bright vegetal yellows; but white lead and
other metalline pigments injure, while terrene and alkaline substances
redden it. In water it works remarkably well, and forms an opaque
emulsion without grinding or preparation, by means of its natural gum;
but is with difficulty employed in oil, &c., in a dry condition. It
dries well, however, in its natural state, and lasts in glazing when
deprived of its gum. With regard to other colours it is perfectly
innocent, and though a strong medicine, is not dangerous or deleterious
in use. Gamboge has been employed as a yellow lake, precipitated upon an
aluminous base; but a better way of preparing it is to form a paste of
the colour in water, and mix it with lemon yellow, with which pigment
being diffused it goes readily into oil or varnish. Glazed over other
colours in water, its resin acts as a varnish which protects them; and
under other colours its gum acts as a preparation which admits
varnishing. It is injured by a less degree of heat than most pigments.
In landscape, gamboge affords with indigo or Antwerp blue clear bright
greens, and with sepia a very useful sober tint. For sunrise and sunset
clouds, a mixture of gamboge and cadmium yellow will be found useful.
32. EXTRACT OF GAMBOGE
Is the colouring matter separated from its greenish gum and impurities
by solution in alcohol, filtration and precipitation, by which it
acquires a powdery texture, rendering it miscible in oil, &c., and
capable of being employed in glazing. At the same time it is improved in
colour, and retains its original property of working well in water with
gum. Gamboge is likewise soluble in caustic potash, forming a red
liquid, from which it is thrown down by acids.
33. INDIAN YELLOW
Is a pigment long employed in India under the name _Purree_, but has not
many years been introduced generally into painting in Europe. It is
imported in the form of balls of a fetid odour, and is produced from the
urine of the camel. It appears to be a urio-phosphate of lime, and is of
a beautiful pure yellow colour and light powdery texture; of greater
body and depth than gamboge, but inferior in these respects to
gallstone. Indian yellow resists the sun's rays with singular power in
water painting; yet in ordinary light and air, or even in a book, the
beauty of its colour is not lasting. In oil it is exceedingly fugitive,
both alone and in tint. Owing probably to its alkaline nature, it has an
injurious effect upon cochineal lakes and carmine when used with them.
The colour is not damaged by foul air, and, as lime does not destroy it,
the pigment may be employed in fresco according to its powers.
Indian yellow washes and works extremely well, and is adapted for
draperies and for compounding landscape greens--where permanency is not
required. Blackness in the darkest shadows of the foliage will sometimes
result from too great a use of indigo; should this evil exist, no colour
is so fitted to regain the proper tone as Indian yellow employed
thickly.
LAKES.
There are several pigments of this denomination, varying in colour and
appearance according to the substances used and modes of preparation.
Usually they are in the form of drops, and their colours are in general
bright yellow, very transparent, and not liable to change in an impure
atmosphere--qualities which would render them very valuable, were they
not soon discoloured and even destroyed on exposure to air and light,
both in water and oil. In the latter vehicle, they are bad driers, like
most lakes, and they do not stand the action of white lead and other
metallic pigments. If used, therefore, it should be as simple as
possible. Of these lakes, the following are the best; but it must be
borne in mind that, as not one of them is permanent, the compounds they
afford are of necessity unstable.
34. YELLOW LAKE
Is a bright transparent yellow, a difficult drier, and liable to be
destroyed by light. It affords beautiful foliage tints, and would, if it
could be depended on, be of extreme value in what is called "glazing."
35. ITALIAN PINK,
Also called _English_ and _Dutch Pink_, is an absurd name for a stronger
and richer kind of yellow lake, warmer in tint and more powerful than
the preceding. It is a rich transparent yellow, yielding a variety of
fine foliage tints by admixture with indigo and sepia in different
proportions. These three colours with burnt sienna will produce almost
every variety of sunny foliage. It gives likewise good olive greens with
lamp black.
36. QUERCITRON LAKE,
Or _Quercitron Yellow_, is what its name implies. It is dark in
substance, in grains of a glossy fracture, perfectly transparent, and
when ground is of a beautiful yellow colour. In painting it follows, and
adds richness and depth to, gamboge in water, and goes well into
varnish; but any lead used in rendering oils siccative, browns it, and
for the same reason it is useless in tints.
37. LEMON YELLOW,
Or chromate of baryta, is exceedingly difficult to make well. Upon the
mode of manufacture depend not only the beauty of the colour but its
stability. If properly and carefully prepared, it is of a vivid lemon
tint, deep or pale, very clear, very pure and permanent. It also washes
well, and is entirely free from the slightest tinge of orange. This may
be pronounced the only chromate which possesses durability, not being
liable to change by damp or foul air, by the action of light or the
steel palette-knife, or by mixture with white lead and other pigments,
either in water or oil, in both of which it works pleasantly. Lemon
yellow is chiefly adapted to points of high light, and has a peculiarly
happy effect when glazed over greens in both modes of painting. In water
it exceeds gamboge in brightness, and compounded therewith improves its
beauty. This mixture also goes readily into oil; indeed it is the best
and easiest way of rendering gamboge diffusible as an oil colour--simple
emulsion of the gamboge in a little water, and trituration of the lemon
yellow therewith, being all that is requisite for the purpose.
Lemon yellow has not much power, and is semi-opaque. In distance, its
light wash is used with great effect for cool sunny greens, for which a
minute quantity of emerald green may be added to it. Being uninjured by
lime, the colour is eligible in fresco and crayons.
38. MARS YELLOW,
_Jaune de Mars_, _Jaune de Fer_, _Iron Yellow_, &c., is an artificially
prepared iron ochre, of the nature of sienna earth. In its general
qualities it resembles the ochres, with the same eligibilities and
exceptions, but is more transparent, as well as purer, clearer, richer,
and brighter. Like them it is quite permanent. The colours of iron exist
in endless variety in nature, and are capable of the same variation by
art, from sienna yellow, through orange and red, to a species of purple,
brown, and black, among which are useful and valuable distinctions. They
were formerly introduced by the author, and have been received under the
names of Mars yellow, Mars orange, Mars red, Mars violet, and Mars
brown. All of them are brighter and purer than native ochres, and
equally stable. When carefully prepared, these pigments dry well in
proportion to their depth, are marked by a subdued richness rather than
brilliancy, and have the general habits of sienna earths and ochres.
Their faint washes possess the desirable quality of transparent
clearness.
We have occasionally found Mars yellow mixed with orpiment, or chromate
of lead, for the purpose of brightening the colour.
39. NAPLES YELLOW
Was a compound of lead and antimony, anciently prepared at Naples under
the name of _Giallolino_, and was variously of a pleasing light, warm
yellow tint. It was opaque and of good body, not altered by the light of
the sun, and might be used with comparative safety in oil or varnish,
under the same management as the whites of lead. Like these, however, it
was liable to change even to blackness by damp and impure air when
employed in water. Iron was also destructive of the colour of this
yellow, on which account great care was requisite, in grinding and using
it, not to touch it with the common steel palette knife, but to compound
its tints with a spatula of ivory or horn. For the same reason, it was
apt to suffer in composition with ochres, Prussian and Antwerp blues,
and other pigments of which iron was a principal or ingredient. Used
pure or with white lead it was eligible in oil, in which it worked and
dried well. It was also employed in enamel painting as it vitrified
without change. In this state it was called _Giallolino di fornace_, and
was introduced as a pigment for artists, under the erroneous conception
that vitrification gives permanence to colours, when in truth it only
increases the difficulty of levigation, and injures their texture for
working. We have spoken of Naples yellow in the past tense, because the
pigment now sold as such is generally, or always, a compound colour, or
manufactured with a zinc instead of a lead base. In either case the
preceding remarks are not applicable to the present product, which is
perfectly durable and trustworthy. The new Naples yellow presents an
example of an old objectionable pigment being replaced by a different
and superior preparation. However fugitive certain colours may have
been, the fact of their once having had a place on the palette would
seem to be sufficient recommendation to some. At any rate, they are
still in occasional request, and we cannot but approve the pious fraud
which offers under the same name a good substitute for a bad original.
If an artist must needs demand a worthless pigment, he had better buy a
colour like it that will stand, even if it be not what he asked for.
The tints of Naples yellow are readily and accurately imitated by
admixture of deep cadmium yellow and white.
40. ANTIMONY YELLOW,
As its name denotes, was likewise a preparation of that metal, of a
deeper colour than Naples yellow, but similar in its properties. It was
principally used in enamel and porcelain painting, and differed greatly
in tint. One variety, brighter than the rest, is stated not to have
been affected by foul air, and therefore could not have had a lead
basis.
OCHRES,
Known as _Yellow Ochre_, _Brown Ochre_, _Roman Ochre_, _Transparent Gold
Ochre_, _Oxford Ochre_, _Stone Ochre_, _Di Palito_, &c., are native
earths, consisting chiefly of silica and alumina in combination with
iron, which latter forms the principal colouring matter. They are among
the most ancient of pigments, and their permanency is proved by the
state of the old pictures. In a box of colours found at Pompeii, and
analyzed by Count Chaptal, he discovered yellow ochre purified by
washing, which had preserved its original freshness. They may all be
produced artificially in endless variety as they exist in nature, and
are all converted by burning into reds or reddish-browns. Several ochres
are found in the natural state of so very fine a quality, that they
require no other preparation than that of being washed. Their colours
may be imitated to a certain extent by means of iron alone, uncombined
with silica and alumina; but such ferruginous preparations are not
equally durable, and as their chemical action is stronger, they are more
likely to affect those pigments which are damaged by iron. It often
happens in colours that one component of weak stability, or powerful
for evil, is strengthened and held in check by another; thus in the case
of the ochres, the silica and alumina by keeping a tight hand on the
iron, both ensure its safety, and prevent it injuring others.
41. YELLOW OCHRE,
Called also _Mineral Yellow_, is found in most countries, and abundantly
in our own. It differs much both in constitution and colour, ranging
from a tolerably bright though not vivid yellow to a brown-yellow, and
is generally of a warm cast. Its natural variety is much increased by
artificial dressing and compounding. The best yellow ochres possess no
great force, but as far as they go are valuable pigments, particularly
in fresco and distemper, being neither subject to change by ordinary
light, nor sensibly affected by impure air, or the action of lime. By
time, however, and the direct rays of the sun, they are somewhat
darkened. Like other ochres, they may be safely used in admixture with
pigments which are themselves permanent. With carmine and the cochineal
lakes, or intense blue, the ochres are best not employed.
The impunity with which yellow ochre bears foul gas is one of its many
recommendations. No immediate effect whatever is produced by
sulphuretted hydrogen, and only a slight dirty brown tint is imparted
by its prolonged action. This discolouration a short exposure to air and
light quickly removes. By keeping the ochre sufficiently long in contact
with sulphide of ammonium a jet black is obtainable, but a rub of it in
a moist unwashed state completely regains its yellow hue in a day or so.
Hence, yellow ochre compounded with pigments which suffer from an impure
atmosphere doubtless acts as a preservative agent.
Yellow ochre is usually employed in the distance and middle ground of a
landscape. It possesses a slight degree of turbidness, and is esteemed
for this property, which is considered to give it a retiring quality. By
admixture with Antwerp blue or indigo it affords a fine range of quiet
greens, also a very serviceable yellowish drab with Vandyke brown. The
ochre is valuable in warm skies, the sails of ships and boats, sandstone
rocks and cliffs, buildings, hay, sheep, &c. It does not compound kindly
with any of the cold colours, and should therefore be used as a wash
over others that are dry, when required to qualify their tints.
42. ROMAN OCHRE
Is rather deeper and more powerful than the preceding, as well as more
transparent and cool in tint. In other respects it is similar, and forms
with Antwerp blue and indigo a like excellent range of greens. We may
observe, however, that as indigo is not a permanent pigment, the colours
it yields by admixture cannot be durable as far as the blue is
concerned. Roman ochre and brown madder are admirably adapted for red
sails, and autumnal effects of foliage.
43. BROWN OCHRE,
Likewise known as _Spruce Ochre_ and _Ocre de Rue_, or, more correctly
_Ru_, is a dense, deep-toned brownish yellow, fine in sandy foregrounds.
With Indian yellow it gives a dark autumnal tint of great richness, but
stable only as respects the ochre. When mixed with other colours, it
furnishes a series of rich yet sober tones of extensive use. It covers
well, without being too opaque; and compounded with black and a little
brown-red is good for backgrounds, &c.
44. TRANSPARENT GOLD OCHRE
Resembles in a great degree Roman ochre, but is clearer in its tints,
and more transparent. It is also brighter and much less opaque than
yellow ochre. It approaches somewhat the character of clear bright raw
sienna, though more pure and brilliant, serving for strong
semi-transparent greens and sunny effects.
45. OXFORD OCHRE
Is a native pigment from the neighbourhood of Oxford, semi-opaque, of a
warm yellow colour and soft argillaceous texture, absorbent of water and
oil, in both of which it may be safely employed. It is one of the best
of yellow ochres.
46. STONE OCHRE
Has been confounded with the last variety, to which, as well as to Roman
ochre, it is frequently similar. True stone ochres are found in balls or
globular masses of various sizes in the solid body of stones, lying near
the surface of rocks among the quarries of Gloucestershire and
elsewhere. These balls are smooth and compact, in general free from
grit, and of a powdery fracture. They vary exceedingly in colour, from
yellow to brown, murrey, and gray, but otherwise do not differ from
ordinary ochres.
In enamel they may be used for browns and dull reds.
47. DI PALITO
Is a light yellow ochre, with no special distinguishing quality, except
that its tints are rather purer in colour than most ochres.
48. ORIENT YELLOW
Is an entirely new preparation of absolute permanence, and perfectly
unexceptionable in all respects, both in water and oil. We can give it
no higher praise than by saying it equals aureolin in stability, as well
as in neither injuring, nor being injured by, other colours. Not
possessed of the same amount of transparency, it is distinguished by
greater richness and depth. Of a soft golden hue, lustrous and luminous,
it resembles a brilliant and somewhat opaque Indian yellow. A gorgeous
and durable substitute for that fugitive pigment is produced by
compounding the orient with aureolin, or by using the latter as a glaze.
Being more transparent than cadmiums and less obtrusive, the new yellow
is adapted for mellow sunset and sunrise clouds, or for sunshine on
distant mountains. With French blue it affords a beautiful sea green;
and, mixed with aureolin, gives fine foliage tints. It is also eligible
for draperies and illumination. For enamelling it is inadmissible, the
colour being destroyed by great heat; but in fresco it may safely be
employed.
As in the case of aureolin, we have had a prolonged personal experience
of this new yellow, an experience which justifies us in asserting that
there is none more permanent. In the whole range of artistic colours
there is no pigment less affected by chemical or physical agents. Acid
and ammoniacal fumes, foul gases, and exposure to damp, air, light, or
sunshine, equally fail to injure it. The perfect impunity with which it
bears the action both of sulphuretted hydrogen and sulphide of ammonium
is remarkable. The former gas may be continuously passed into the colour
suspended in water, or a strong solution of the latter sulphide be
poured upon it, and the yellow remains unchanged. Submitted to the
direct rays of the sun during an entire summer, its lightest and
faintest tints have preserved their original hue.
In a preceding chapter we remarked that, provided the colour be stable,
the more colour a pigment possesses the better. The "latent colour"
there alluded to, is one of the advantages of orient yellow. The more it
is looked into, the more colour is seen--there is no suspicion of a base
coloured, the pigment is colour itself.
49. ORPIMENT,
Also called _King's Yellow_, _Chinese Yellow_, _Yellow Orpiment_, &c.,
was known in ancient times: the Romans called it _auri pigmentum_ or
gold colour, whence, by corruption, its present name is derived. It is
found in the native state in China and elsewhere, the best quality being
in masses, consisting of plates of a fine golden hue, intermixed with
portions of a vermilion or orange-red colour; the inferior kinds are
yellow or greenish yellow. Of orpiment, or sulphuret of arsenic, which
is produced artificially, there are two distinct varieties; one of a
bright pure yellow tint, in which the sulphur predominates, and one of
an orange hue, in which the arsenic is in excess. The former is the most
lasting, but it is not durable in water, and still less so in oil,
although not discoloured by impure air. Compounded with white lead it is
soon destroyed, nor can it be mixed with any colours into which lead
enters, such as chrome yellow, the old Naples yellow, &c. The sulphur in
combination with the arsenic, having less affinity for that metal than
for lead, lets it go, and forms a sulphuret of lead of a dark greyish
hue. Moreover, as orpiment is apt to deprive other pigments of their
oxygen, and therefore to change and be changed by all pigments whose
colour depends on that element--metallic pigments especially--it is
probable that the orpiment after some time withdraws the oxygen from the
lead; and this would be an additional cause for the darkening of the
tint composed of the two colours. With sulphides or pigments containing
sulphur, orpiment may be used with less danger. If employed at all,
however, it had better be in a pure and unmixed state. We are far from
recommending orpiment as an eligible colour, and it is highly
poisonous.
Brick dust and yellow ochre are sometimes found as adulterants.
50. RAW SIENNA,
Known likewise as _Raw Sienna Earth_, _Terra di Sienna_, &c., is a
ferruginous native pigment, firm in substance, of a glossy fracture, and
very absorbent. It is of rather an impure yellow colour, and much used
in landscape, being very serviceable both in distance and foreground.
Unless proper skill is exercised in its preparation, the sienna has the
objection of being somewhat pasty in working. Being little liable to
change by the action of either light, time, or impure air, it may safely
be employed according to its powers, in oil, water, and other modes of
practice. It possesses more body and transparency than the ochres; and
by burning becomes deeper, orange-russet, as well as more transparent
and drying.
Raw sienna compounded with cobalt, indigo, or Prussian blue, and a very
little bistre, yields good sea greens, that with indigo being the most
fugitive. Alone, it is adapted for shipping, sails, baskets, decayed
leaves, brooks and running streams.
51. STRONTIAN YELLOW,
To justify its name, should be a chromate of strontia, a compound very
slightly soluble in water, and not more stable than the zinc chromate.
The pigment, however, now sold as strontian yellow is usually formed by
admixture, and contains no strontia whatever. Its absence cannot be
considered a disadvantage, for the substitute possesses a durability to
which the original could lay no claim. Other things being equal, we
prefer an original pigment to one compounded, but a good mixture is
decidedly better than a bad original. A light primrose, clear and
delicate.
* * * * *
The foregoing comprise those yellows more generally employed, advisedly
or not, as the case may be. The following are for the most part not
commercially obtainable, a remark that will apply in ensuing chapters to
all numbered colours printed in italics. As a rule, these have become
obsolete as pigments, or have never been introduced as such. The former
could not well be omitted in a work of this kind, and the latter deserve
notice as being at least suggestive. At present, many of them must be
regarded as mere curiosities, being obtainable only from materials of
excessive rarity. In time, however, the sources whence they are derived
may possibly be found in greater abundance, and these now fancy products
prove of value to the palette. The new metal indium, for instance,
furnishes a bright yellow sulphide, like that of cadmium. The colour
could not be affected by foul air, and might possess other advantages
which would render indium yellow a desirable pigment. With regard to
those compounds available for artistic use, but which have not to our
knowledge been adopted, several are quite ineligible. It may be thought
that they are needlessly referred to, but they are mentioned as a
warning and a guide. Strange preparations have been offered as pigments,
and sometimes accepted, witness turbith mineral, iodine yellow, &c. In
these days of chemistry there is less chance for them, but they are
continually submitted to one's notice, their merits being enlarged upon
in proportion to their worthlessness. Through an exceptional ignorance
they may still gain a place, and it has been deemed, therefore, not
superfluous to allude to them. At the same time we do not pretend to
exhaust the list, any more than we claim to note all substances
possessing colour, but yet not admissible as pigments. Some there are
which do not retain that colour on drying; others, whose preparation
involves processes too nice, complicated, or expensive, for
manufacturing purposes. There are many colours, again, which exist only
on paper. We have too often found the imaginations of chemical writers
far more vivid than the colours they describe. Gorgeous yellows turn
out dingy drabs; dazzling scarlets dirty reds; and brilliant blues dusky
slates. As respects colours, most books of science need revising.
52. _Arsenic Yellow_,
Called also _Mineral Yellow_, has improperly been classed as an
orpiment, from which it differs in not being a sulphide, and in
containing lead. It is prepared from arsenic fluxed with litharge, and
reduced to powder. It is much like orpiment in colour, dries better, and
not being affected by lead, is less liable to change in tint. The
presence of the litharge, however, renders it subject to be blackened by
sulphuretted hydrogen. Of course it is poisonous.
53. _Bismuth Yellow_,
Or chromate of bismuth, may be obtained either as a lemon or an orange
yellow, sparingly soluble in water. The colour is not permanent, and
turns greenish-brown even when excluded from light and air.
54. _Copper Yellow_,
Or chromate of copper-potassa, is of a bright yellow tint, not insoluble
in water. It is discoloured both by foul gas and exposure.
55. _Gelbin's Yellow_,
Or chromate of lime, is a pale whitish yellow, poor in colour, partly
soluble, and not at all to be depended on.
56. _Indium Yellow._
Whether the new metal indium will ever be found in sufficient quantity
to render it practically useful remains to be seen. The most abundant
source at present known is the Freiberg blende, 100,000 parts of which
only yield from twenty-five to forty parts of indium. The metal is
chiefly interesting in an artistic sense on account of its sulphide, a
fine bright yellow resembling cadmium, and best obtained by
precipitating an acetic acid solution with sulphuretted hydrogen, or
sulphide of ammonium. In the latter, the yellow dissolves on being
heated, but deposits again on cooling of a rather paler tint. With one
modification, what was said in a former edition of this Treatise
concerning cadmium yellow may be repeated of indium yellow. "The metal
from which it is prepared being hitherto scarce, it has not been
employed as a pigment, and its habits are not therefore ascertained."
All we can tell is, that the colour does not suffer from impure air.
Indium is likewise distinguished by a straw-yellow oxide.
57. _Iodine Yellow_,
Or iodide of lead, is one of those compounds whose presence on the
palette should never have been allowed. Exceedingly brilliant, it is
also utterly fugitive, destroyed by exposure or foul gas, and useless in
admixture. We may state here that, whatever its colour, no pigment
containing iodine can in the slightest degree be relied upon. One of the
most unstable of substances, being slowly volatile even at common
temperatures, iodine is or ought to be quite inadmissible as a
constituent. Combined with lead, which is in itself objectionable, it
forms a yellow possessing every bad quality.
58. _Iron Yellow_,
Or oxalate of protoxide of iron, has very unadvisedly been recommended
as a pigment. It is a bright pale yellow, but soon loses the beauty of
its tint when submitted to air and light, becoming, by peroxidation, red
and buffy. Even in a book the colour changes.
59. _Madder Yellow._
As our (the Editor's) experience of this product is somewhat at variance
with that of the author, we subjoin his original statement. "Madder
yellow is a preparation from the madder-root. The best is of a bright
colour, resembling Indian yellow, but more powerful and transparent,
though hardly equal to it in durability of hue; metallic, terrene, and
alkaline substances acting on and reddening it as they do gamboge: even
alone it has by time a natural tendency to become orange and foxy. We
have produced it of various hues and tints, from an opaque and ochrous
yellow, to a colour the most brilliant, transparent, and deep. Upon the
whole, however, after an experience of many years, we do not consider
them eligible pigments."
While agreeing with Mr. Field as to the character given of these
yellows, we must confess that we have never been able to obtain, nor
have we ever seen, a "most brilliant" madder yellow. Colours bearing
that name have come under our notice, but if their hue was pure and
vivid, they have always proved to be falsely so called, the madder being
conspicuous by its absence. What we have succeeded in producing, and the
genuine samples we have met with, have been fawns, buffs, drabs, &c.,
decidedly "ochrous" yellows, and wanting in stability. It is certain
that no true madder yellow, brilliant and pure, ranks as a pigment at
the present day. A variety known as Cory's Yellow Madder may be briefly
described as Cory's _Brown_ Madder.
60. _Massicot_,
Or _Masticot_, is a protoxide of lead, varying from the purest and most
tender straw colour to a dull orange yellow, and known as Light, Yellow,
and Golden Massicot. It has in painting all the properties of white
lead, from which it may be prepared by gentle calcination in an open
furnace. In tint with that pigment, however, it soon loses its colour
and returns to white, probably extracting some carbonic acid therefrom.
If used in an unmixed state, it is permanent in oil under the same
conditions as white lead, but should not be employed in water, on
account of its changing even to blackness by the action of damp or
impure air. It is an admirable dryer, and has much the same effect as
litharge in rendering oils siccative.
_Litharge_ is merely fused massicot. Old writers speak of litharge of
silver and litharge of gold, oxides of lead, pale and reddish yellow
respectively. Commercial litharge, especially that which is foreign,
contains sometimes a considerable proportion of oxide of copper and
iron. The principal impurity, however, is generally silica, left
undissolved on treating the litharge with nitric or acetic acid.
Litharge is commonly used in preparing drying oils, which contain a
greater or less amount of the oxide in the form of oleate of lead. Oils
made siccative by means of litharge are therefore liable to be damaged
by foul gas. It is a matter of congratulation that such injury is not
lasting, and that the oil, like white lead, recovers its original colour
on exposure to air and light. Some drying oil which we exposed on a tile
to an atmosphere of sulphuretted hydrogen until it was completely
blackened, regained its former yellow hue on being submitted for a day
or so to air and light. Hence, although the employment of lead as a
siccative is not desirable, its effects are not so deleterious as might
be imagined.
61. _Patent Yellow_,
_Turner's Yellow_, _Montpellier Yellow_, _Mineral Yellow_, _Cassel
Yellow_, &c., is a mixture of chloride and oxide of lead, obtainable
either as a pale or a deep yellow. It is a hard, ponderous, sparkling
substance, of a crystalline texture and bright colour; hardly inferior,
when ground, to chrome yellow. Of an excellent body, and working well in
oil and water, but soon injured both by the sun's light and impure air.
A variety, mentioned by Mérimée, in which bismuth and antimony are also
used, is of greater durability.
62. _Platinum Yellow._
Our own opinion of this costly preparation is that the good qualities of
the product do not justify its price. It may be obtained as a bright,
rich, deep yellow, of considerable transparency; but the colour is acted
upon by foul gas and exposure. Even in a book we have found it assume a
dirty greyish cast, and a specimen which had been kept in a drawer,
wrapped up in paper, became perfectly black in a few years. The presence
of palladium interferes with the beauty of the original tint, but does
not affect its stability.
63. _Thallium Yellow._
The new metal thallium yields in combination with chromic acid two
yellow colours, a pale and an orange. They are not absolutely insoluble
in water, and the sulphide of thallium being brown, would probably be
damaged by impure air. But whatever their properties as pigments may be,
their habitudes as such are not yet known. The present scarcity of the
metal renders the colours produced from it mere scientific curiosities.
64. _Thwaites' Yellow._
Under this name chromate of cadmium was introduced some few years back.
If well prepared, it is a fine soft powder of a very vivid light yellow
colour. The compound is too soluble, however, to be of value, its
washings even with cold water being continually tinged yellow. Hence it
turns green after a time, and becomes otherwise discoloured. Like
citron yellow and other chromates apt to assume a green cast, it should
only be employed, if at all, when compounded for foliage tints, &c. This
want of durability is to be regretted, for a good sample of cadmium
chrome is marked by exceeding beauty, unsurpassed for clearness and
purity by any other yellow.
65. _Turbith Mineral_,
Or _Queen's Yellow_, is a subsulphate of mercury, of a beautiful lemon
yellow colour, but so liable to change by the action of light or impure
air, that it cannot be used safely, and hardly deserves attention as a
pigment.
66. _Uranium Yellow_
Can be produced of a pale or orange tint, differing in brightness and
depth of colour according to the mode of preparation. It is fairly
eligible as a pigment, and far superior to the many fugitive compounds
which have from time to time appeared. Being very expensive, however,
and not possessing the good qualities of its compeers lately introduced,
uranium yellow has but little chance of being employed now.
67. _Yellow Carmine_
Is a rich transparent colour, somewhat resembling an ochre compounded
with Indian yellow. On exposure to light, it behaves much as a mixture
of those pigments would do, the rich _yellowness_ entirely disappearing,
and the sober-coloured earth being left behind.
* * * * *
From several metals besides those mentioned, yellows more or less vivid
and durable may be obtained--from tin, nickel, cerium, molybdenum, &c.;
but we do not know that any one of them would be a really desirable
addition. To justify its being brought out, a new pigment should own
some special advantage, chemical or artistic, by which it may be
distinguished from other colours. No purpose would be answered by
crowding the palette with mere repetitions, even though they were
stable. If, for instance, indium yellow were found exactly similar to
that of cadmium, in colour, opacity, permanence, its presence would be
quite superfluous. The mistake is often made of offering a fresh
compound for a pigment when something as good or better, and cheaper may
be, already exists. We remember a patient experimenter, who had produced
a pink from cobalt, wondering why his colour should be so generally
declined. The product was not wanting in either beauty or stability, but
he forgot that the lakes of madder were far more beautiful, at least as
durable, and much less expensive. We have said that we do not join in
the cry of there being too many pigments, or share the opinion that
there is not room for more, but we do enforce the necessity of progress.
Let us have as many good colours as possible, but let the new be
superior to the old, and all be distinct from each other.
As far as yellows are concerned, the palette possesses both variety and
durability. Opaque or transparent, bright or subdued, deep or pale, it
presents a sufficiency of permanent pigments. Most noteworthy are
aureolin, the deep and 'pale' cadmiums, lemon yellow, Mars yellow, the
modern Naples yellow, the ochres, orient yellow, and raw sienna. Whether
used alone or in tint these are, if genuine, perfectly reliable, and
comprise the list of those durable colours which may be called pigments
of the first class.
Among pigments of the second class, or the semi-stable, gamboge holds
the foremost place, for although not strictly durable in itself, it
conduces to the permanence of other colours. Chrome yellows, citron
yellow, strontian yellow, and Thwaites' yellow, also belong to this
division.
As third class pigments, or the fugitive, must be ranked Mutrie yellow
and other lemon cadmiums, the true gallstone, Indian yellow, the lakes,
orpiment, Gelbin's yellow, massicot, patent yellow, and turbith mineral.
It must not be forgotten, however, that these three classes are subject
to modification. A durable pigment may be so adulterated as to descend
to the second or even the third division, while a semi-stable or
fugitive colour may be replaced by a permanent or comparatively
permanent substitute, as in the case of strontian yellow and gallstone.
It should likewise be remembered that pigments are apt to vary in
stability according to the mode of their preparation; and that, as there
are different degrees of permanence, there are different degrees of
fugacity.