Field's Chromatography Part 23

A yellow-brown, so yellow that it might fairly have been cla.s.sed with the ochrous colours of that denomination, is made by combining zinc with another metal by the aid of heat. Experience tells us that it is, chemically, a thoroughly good and stable pigment. Safely to be used in admixture, it is a clear, bright colour, affording good greens by compounding with blue. Of no great power, and semi-opaque, this yellow-brown or brown-yellow is superior to some of the pigments at present used, but is probably too much like them in hue and other properties to be of any special value.

Besides the preceding, there are those browns of a citrine or russet cast which are elsewhere described, such as raw umber, madder brown, &c.

Moreover, there are numberless other varieties, obtainable from most of the metals, from many organic substances, and from a combination of the two. Of all colours, a 'new' brown is the most easily discovered: success may not be met with in seeking a yellow, red, or blue, or an orange, green, or purple; but it is strange if in the course of one's experiments a brown does not turn up. No difficulty, therefore, would have been found in greatly extending the present list; but it was felt that no advantage could have accrued by further multiplying the notices of a colour, with which we are already furnished so abundantly by nature and art, and which is capable of being produced in such profusion by admixture.

With the exception of ivory and bone browns, and perhaps Ca.s.sel and Cologne earths, all the browns commonly employed may be considered more or less durable.

CHAPTER XVIII.

ON THE SEMI-NEUTRAL, MARRONE.

We have adopted the term MARRONE, or _maroon_ as it is sometimes called, for our second and middle semi-neutral, as applicable to a cla.s.s of impure colours composed of black and red, black and purple, or black and russet, or of black and any other denomination in which red predominates. It is a mean between the warm, broken, semi-neutral _browns_, and the cold, semi-neutral _grays_. Marrone is practically to shade, what red is to light; and its relations to other colours are those of red, &c., when we invert the scale from black to white. It is therefore a following, or shading, colour of red and its derivatives; and hence its accordances, contrasts, and expressions agree with those of red degraded; consequently red added to dark brown converts it into marrone if in sufficient quant.i.ty to prevail. In smaller proportions, red gives to lighter browns the names of bay, chestnut, sorrel, &c.

Owing to confused nomenclature, most of the colours and pigments of this cla.s.s have been a.s.signed to other denominations--puce, murrey, morelle, chocolate, columbine, pavonazzo, &c., being variously ranked among reds, browns, and purples. This vagueness also accounts for pigments having been ranged under heads not suited to the names they bear, and explains why Brown Ochre has been cla.s.sed among the yellows, Italian Pink among the same, Brown Pink among the citrines, &c.

As adapted to the walls of a picture gallery, marrone, more or less deep and inclined to crimson, is one of the best colours known. For the reason that each colour has its antagonist, and consequently may affect a picture well or ill, according to its tone or general hue, there can be no universally good colour for such a purpose. What suits one picture or style of painting may not suit another: with a blood-red sunset, for instance, or portrait with crimson drapery, marrone would be out of place. But as it is impossible to provide each picture with a separate background, all that can be done in large collections is to study the general effect, sacrificing the interests of the few to the good of the many. If cool-coloured landscapes predominate, with blue skies and green foliage, it will be found that the orange-yellow of the frames agreeably contrasts the former, and the crimson-marrone of walls as agreeably sets off the latter. If portraits and historic paintings prevail, which are in general of a warm advancing nature, then a modest green may prove eligible. And if engravings form the staple, the grey hue of the print is best opposed by a bright fawn colour. Where several rooms are devoted to pictures, a suitable wall colour is most easily secured by cla.s.sifying the paintings as far as possible according to their general hue, and placing them in different chambers: in each there will be a prevailing character in the colouring of its pictures, and each can be painted or papered accordingly. However, whether this plan is adopted or not--and it may be objected to as involving a certain monotony--care should be taken to have a wall colour of some sort or other, that is, to let it be seen. Pictures crammed together kill each other: without a pin's point between them, a speck of wall s.p.a.ce visible, much of the illusion is destroyed. "It is only," says Chevreul, "the intelligent connoisseur and amateur who, on seeing a picture exhibited in a gallery, experience all the effect which the artist has wished to produce; because they alone know the best point of view, and because, while their attention is fixed on the work they are observing, they alone end by no longer seeing the surrounding pictures, or even the frame of that one they contemplate." Amid a moving crowd of people, inseparable from nearly all public exhibitions, it becomes difficult for the visitor, intelligent or otherwise, thus to concentrate his attention on one work.

As far, therefore, as s.p.a.ce will allow, paintings should be kept separate: larger rooms, or fewer pictures, are what is wanted.[B]

From this digression, pardonable, let us hope, because in the interests of art, we will pa.s.s on to a consideration of marrone pigments.

276. BROWN MADDER

is an exceedingly rich marrone or russet-marrone brown, bearing the same relation to the colour marrone that raw umber bears to the colour citrine. One of the most valuable products of the madder root, it has supplied a great desideratum, and in water especially is indispensable, both as a local and auxiliary colour. Of intense depth and transparency, if made with skill, it affords the richest description of shadows, either alone or compounded with blue, and the most delicate pale tints.

Being quite permanent, a good drier, and working most kindly, it is a pigment which cannot be too strongly recommended to the landscape painter's notice. Containing a large proportion of red, it is eligible, with yellow or blue, for mixed orange or mixed purple of a subdued tone.

It may be used tolower red curtains or draperies, and for the darkest touches in flesh. Mixed with cobalt, it forms a fine shadow colour for distant objects; and with indigo or Prussian blue and black, is serviceable for the shades of those nearer the foreground. It is similarly useful when mixed with black, and will be found advantageous in rusty iron, as anchors, chains, &c. For the deepest and richest parts of foregrounds it may be employed alone, as also for deep dark cracks and fissures, or strong markings in other near objects, as boats and figures. With French blue, or cobalt and white, a set of beautiful warm or cold grays may be obtained, in proportion as the brown or blue predominates. Compounded with blues and bright yellows such as aureolin, it gives fine autumnal russet greens. A good purple for soft aerial clouds is furnished by cobalt and brown madder, or for stormy clouds by the brown, Prussian blue, and black: an equally good slate colour is obtained from cobalt, sepia, and the brown. For glazing over foliage and herbage, a mixture of the madder with aureolin or gamboge is adapted; and for brooks and running streams compounds of this brown with raw Sienna, cobalt and raw Sienna, Vand.y.k.e brown, and French blue, will each be found useful. Black sails are well represented by burnt Sienna, French blue, and brown madder; and red sails by light red or burnt Sienna with the brown.

277. MIXED MARRONE.

Marrone is a retiring colour easily compounded in all its hues and shades by the mixture variously of red, and black or brown; or of any other warm colours in which red and black predominate. A reference to the permanent brown, black, and red or reddish pigments will show to what extent the colour marrone may safely be produced by admixture. In compounding marrone, the brown or black may be itself compounded, before the addition of the red, reddish-purple, or russet, requisite for its conversion.

278. _Chica Marrone_.

Chica, the red colouring principle alluded to in the ninth chapter, is extracted from the _Bignonia chica_, by boiling its leaves in water, decanting the decoction, and allowing it to cool, when a red matter falls down, which is formed into cakes and dried. Insoluble in cold water, it dissolves in alcohol and alkalies; is precipitated from alkaline solutions by acids without alteration; and is bleached by chlorine. Another variety of the same substance, obtained from Para in Brazil, and known as crajuru, carajuru, or caracuru, behaves in a similar manner. This is said to be superior to the former sort.

A chica pigment, brought from South America, and examined by the author, was of a soft powdery texture, and rich marrone colour. Somewhat resembling Rubens' madder in hue, it was equal in body and transparency to the carmine of cochineal, though by no means approaching it in beauty, or even in durability. Simply exposed to the light of a window, without sun, the colour was soon changed and destroyed. Conclusive evidence as this is that the sample submitted to Mr. Field was worthless, it remains to be seen whether all the colours to be derived from chica, by different modes and from different kinds, are equally valueless as pigments.

279. _Chocolate Lead_,

or Marrone Red, is a pigment prepared by calcining oxide of lead with about a third of copper oxide, and reducing the compound to a uniform tint by levigation. It is of a chocolate hue, strong opaque body, and dries freely. Like all lead and copper colours, it is blackened by impure air.

280. _Cobalt Marrone._

There is obtainable from cobalt a very rich marrone brown, which, like many other colours, is more beautiful while moist than when dried.

Permanent, if carefully made and most thoroughly washed, it is an expensive compound, and must rank among those colours which are interesting in the laboratory but superfluous in the studio.

281. _Madder Marrone_,

or Marrone Lake, was a preparation of madder, of great depth, transparency, and stability. Working well in water, glazing and drying in oil, and in every respect a good pigment, it was one of those colours which gradually--and often, as in this case, unfortunately--become obsolete, on account of their hues being easily given by admixture of other pigments. There was likewise a deeper kind, called Purple Black. A good madder marrone may be produced by adding to brown madder either rose madder, madder carmine, or Rubens' madder, with a slight portion of black or blue if required.

282. _Mars Marrone._

Under the heading of a New Marrone Pigment there appeared some months back in a chemical journal the following:--"The blood-red compound obtained by adding a soluble sulphocyanide to a salt of iron in solution can be made (apparently at least) to combine with resin thus: To a concentrated solution of sesquichloride of iron and sulphocyanide of pota.s.sium in ether, an etherial solution of common resin is added, and the whole well shaken together. There is then mixed with it a sufficiency of water to cause a precipitate, when it will be found, after the mixture has stood a few hours, that the whole or nearly the whole of the red-coloured iron compound has united with the precipitated resin, forming the marrone-coloured pigment in question. When this coloured substance is finely powdered and mixed with water, the liquid is not the least coloured; whence it is inferred that the red iron compound has chemically united itself with the resin."

The foregoing account is rather to be regarded as of scientific interest than of practical utility. The blood-red solution of sulphocyanide of iron is in itself not stable: when the red solution of this salt is so exposed to the sun, that the rays pa.s.s through the gla.s.s jar containing it, it is rendered colourless, but the colour is retained or restored when the rays pa.s.s directly from the air into the fluid; so that when a properly diluted solution is placed in a cylindrical gla.s.s vessel in direct sunshine, it loses colour in the morning till about eleven in the forenoon, when the rays beginning to fall upon the surface exposed to the air, gradually restore the colour, which attains its maximum about two o'clock. Moreover, the solution is immediately decolourised by sulphuretted hydrogen and other deoxidizing agents, as well as by alkalies and many acids. It is scarcely probable that the union of the red colouring matter with the resin would suffice to secure it from change; and there is little doubt that the new marrone pigment would be a chameleon colour.

Failures in the process of burning carmines, and preparing the purple of gold, frequently afford good marrones. Compounds more or less of that hue are likewise furnished by copper, mercury, &c. Some ochres incline to marrone when calcined: indeed we have remarked in many instances that the action of fire antic.i.p.ates the effects of long continued time; and that several of the primary and secondary colours may, by different degrees of burning, be converted into their a.n.a.logous secondary, tertiary, or semi-neutral colours.

The one marrone or brown-marrone pigment at present employed, brown madder, is permanent.

FOOTNOTES:

[B] This was written previous to the opening of the new rooms of the Royal Academy at Burlington House. In these, among other improvements, the subject of wall s.p.a.ce has been considered.

CHAPTER XIX.

ON THE SEMI-NEUTRAL, GRAY.

Of the tribe of semi-neutral colours, GRAY is third and last, being nearest in relation to black. In its common acceptation, and that in which we here use it, gray, as was observed in the third chapter, denotes a cla.s.s of cool cinereous colours faint of hue; whence we have blue grays, olive grays, green grays, purple grays, and grays of all hues, in which blue predominates; but no yellow or red grays, the prevalence of such hues carrying the compounds into the cla.s.ses of brown and marrone, of which gray is the natural opposite. In this sense the _semi-neutral_ Gray is distinguished from the _neutral_ Grey, which springs in an infinite series from the mixture of the neutral black and white. Between gray and grey, however, there is no intermediate, since where colour ends in the one, neutrality commences in the other, and vice versa. Hence the natural alliance of the semi-neutral gray--definable as a cool coloured grey--with black or shade; an alliance which is strengthened by the latent predominance of blue in the synthesis of black, so that in the tints resulting from the mixture of black and white, so much of that hue is developed as to give apparent colour to the tints. This explains why the tints of black and dark pigments are colder than their originals, so much so as in some instances to answer the purposes of positive colours. It accounts in some measure for the natural blueness of the sky, yet not wholly, for this is in part dependent, by contrast, upon the warm colour of sunshine to which it is opposed; for, if by any accident the light of nature should be rendered red, the colour of the sky would not appear purple, in consequence, but green. Again, if the sun shone green, the sky would not be green, but red inclined to purple; and so would it be with all colours, not according to the laws of composition, but of contrast; since, if it were otherwise, the golden rays of the sun would render a blue sky green.

The grays are the natural cold correlatives, or contrasts, of the warm semi-neutral browns, as well as degradations of blue and its allies.

Hence blue added to brown throws it into or toward the cla.s.s of grays, and hence grays are equally abundant in nature and necessary in art: in both they comprehend a widely diffused and beautiful play of retiring colours in skies, distances, carnations, and the shadowings and reflections of pure light, &c. Gray is, indeed, the colour of s.p.a.ce, and has therefore the property of diffusing breadth in a picture, while it furnishes at the same time good connecting tints, or media, for harmonizing the general colouring. Consequently the grays are among the most essential hues of the art, though they must not be suffered to predominate where the subject or sentiment does not require it, lest they cast over the painting that gloom or leaden dulness reprobated by Sir Joshua Reynolds; yet in solemn works they are wonderfully effective, and proper ruling colours. Nature supplies these hues from the sky abundantly and effectively throughout landscape, and Rubens has employed them as generally to correct and give value to his colouring, with fine natural perception in this branch of his art: witness his works in the National Gallery, and in that of the Luxembourg.

According to the foregoing relations, grays favour the effects and force of warm colours, which in their turn also give value to grays. It is hence that the tender gray distances of a landscape are a.s.sisted, enlivened, and kept in place by warm and forcible colouring in the foreground, gradually connected through intermediate objects and middle distances by demi-tints declining into gray; a union which secures full value to the colours and objects, and by reconciling opposites gives repose to the eye. As a general rule, it may be inferred that half of a picture should be of a neutral hue, to ensure the harmony of the colouring; or at least that a balance of colour and neutrality is quite as essential to the best effect of a painting as a like balance of light and shade.

283. MINERAL GRAY,

or Mineral Gr_e_y, as it is often improperly spelt, is obtainable from the lapis lazuli, after the blue and ash have been worked out. So derived, it is a refuse article, worthless if the stone has been skilfully exhausted of its ultramarine. As this is now generally the case, the best mineral gray is no longer a waste product, but a lower species of ash, a pale whitish blue with a grey cast. Possessing the permanence of ultramarine, it may be regarded in colour as a very weak variety of that blue, diluted with a large quant.i.ty of white slightly tinged by black. A pigment peculiar to oil painting, it is admirably adapted to that gray semi-neutrality, the prevalence of which in nature has been just remarked. For misty mornings, cloudy skies, and the like, this gray will be found useful.

284. MIXED GRAY

is formed by compounding black and blue, black and purple, black and olive, &c.; and is likewise produced by adding blue in excess to madder brown, sepia, &c., transparent mixtures which are much employed. It should be borne in mind that the semi-neutrals, like the secondaries and tertiaries, may be so compounded as to be permanent, semi-stable, or fugitive. The due remembrance of this cannot be too strongly insisted upon, seeing that in every picture the browns and grays are of frequent occurrence. These it is that lend such charm to the whole, flowing, as it were, like a quiet under-current of colour beneath the troubled surface of more decided hues. In the work of every true artist--between whom and the mere painter there is as much difference as between the poet and the poetaster--there is sentiment as well as colour, whether the subject be an exciting battle-scene or a bit of still life. This sentiment, as strongly felt as the colour is clearly seen, is imparted in no small degree by the skilful use of semi-neutrality, the compounding of which, as time goes on, will therefore affect a picture for good or for evil.

Subjoined is an a.n.a.lysis of the three semi-neutrals, which serves partly to show in what great variety they may be obtained by admixture.

Brown = Black + Yellow } " = " + Orange } + Red, Purple, &c.