Colors in Art.*

The Living age 1892, 18.9.1880

* A Handbook for Painters and Art Students on the Character and Use of Colors, their Permanent and Fugitive Qualities, and Vehicles proper to Employ. Also Short Remarks on the Practice of Painting in Oil and WaterColors. By W. J. Muckley. London: Baillière, Tindall, & Cox, 1880.From Nature.

That a book for the instruction of artists as to the composition and purity of their pigments is much needed can hardly be denied. The difficulty, however, in writing such a book is very great; for it must either be very incomplete or contain a large amount of matter which but very few artists can understand. And no one is competent to write such a book but he who has some knowledge of painters' manipulations and a very good knowledge of chemistry; to drop the chemistry and take upon faith what has been written about the purity and nature of pigments, is hardly the method which should be adopted, and the person who does it is not likely to be a very safe guide to the artist, although he may give very many useful hints, and state much that is true. To treat of colors properly their composition must be described and the adulterations to which they are liable should be explained, which cannot be done without a certain amount of chemistry and chemical terms, and if the persons who read a book on pigments know nothing about chemistry, how can they be benefited by it? And this is difficulty number two. How is it to be overcome? Why, simply by artists learning something of chemistry. There is no other way for it. A book so incomplete as that under consideration is very misleading, because a person after reading it will know but little more about pigments than when he began. Of what use is it to know that cadmium yellow is a "sulphide of the metal cadmium," and that "emerald green is a preparation of copper," unless it be known that the elements which compose each have a decided liking for changing places, and that if these pigments are brought into contact the change will assuredly take place to the entire destruction of the tint of both of them? The real truth of the matter is that until artists will consent to become, to a certain extent, students of science, they will never get out of their difficulties, and if they will consent to this, to some of them we fear derogatory task, they will find that there is more help for them from science than they imagined: chemistry will lead to physics, and then for the first time perhaps many of them will learn what color is, and what light and shade really are, and new views will burst upon them, and new methods of using their pigments will become necessary. and then pictures will be resplendent with nature's tints, and transparency will replace opacity, and nature will have some chance of being fairly represented. There are many artists who are scientific men, and there are others to whom nature has given special powers; and these show by their works that they understand or appreciate the true nature of color and of light and shade. Look at Mr. Brett's seapieces (he is a scientific man of note): they are bright, luminous, and true to nature, although they may not please painters of the old school, one of whom once, when asked what he thought of one of this artist's pictures, was heard to say he did not like rocks. As an illustration of one who lays no claim to be a scientific man, take Mr. Herbert's painting of "Moses" in the House of Lords, where bddies of the color nearly of the sandy background stand out from it without any tricks, with all the vivid distinctness of a stereoscopic picture.

To those who know nothing of chemistry what directions can be given for the use of paints which in themselves are stable, but which cannot be mixed with certain others? It would take a huge volume to record all the cases in which they could be used, and to note all the contingencies which might arise to influence them, and yet a little sound chemical knowledge would make the matter easy and brief. Good champagne is a good and wholesome wine, and good old port is a nectar fit for the gods, and hock and claret are cooling drinks which, with their fragrant bouquets, appeal to the imagination: all are rood and wholesome; but mix them all in the same stomach at a great feast, and what will be the result, at feast in most cases? Vermilion is a good and safe pigment, so is cadmium yellow, and so is emerald green; but mix them all together and what will happen? Keep the emerald green and the cadmium apart by some hard and quick-drying vehicle, and all will be well; allow a dayrs interval to elapse between taking the champagne and hock, and port and claret, and no inconvenience will be experienced.

It is very refreshing to read from the pen of Mr. Muckley the warning which he gives to artists to restrict the number of colors which they employ. It is to the use of bright and new tints with which the French colormakers tempt our artists that much of the evil complained of is due, and moreover the adulteration practised abroad, but rarely in this country, has added to it. Mr. Muckley has divided pigments into "permanent colors" and "useless pigments." Speaking of "whites," he very justly recommends zinc white as being permanent, but then he speaks of "flake white" as permanent, but confesses that it loses "its opacity by age," and that "impure air and sulphuretted hydrogen turn white lead" (i.e. flake white) "to a dirty brown in a short time." One would hardly rank this among permanent colors. Amongst yellow he mentions "lemon yellow" as not altogether trustworthy. Now lemon yellow is chromate of baryta, and, like all other chromates, is liable to reduction by organic matter, and then, as it becomes reduced, its tint changes to green. Although he ranks this pigment among "permanent colors," he does so with a caution; why then place it in this list? "Aureolin" is also included in it; but very grave doubts are entertained of its stability in oil by many artists. It certainly resists the action of alkalies fairly well.

"Naples yellow," a pigment which portrait and figure painters have a great affection for, is now a compound made in imitation of the old paint, which consisted of antimony and lead; it was usually some time ago made with white lead tinted with some yellow pigments. If made with zinc white and cadmium, as Mr. Muckley asserts, there is not much danger in using it.

Amongst the "useless pigments" which are said to be "stable" it should be remarked that the whites, "blanc d'argcnt or silver white," "London and Nottingham white," are both white lead, and therefore subject to the same influences as "flake white." "Scheele's green," which is an arsenite of copper, can hardly be called a "stable" color, "but unnecessary."

"Semi-transparent colors." Amongst these is placed "cremintz white." Why this should be it is difficult to understand, if flake white is to be ranked among permanent colors, for cremintz white is white lead produced by precipitation.

"Prussian blue" is spoken of as not being durable; it is quite certain that it stands well sometimes, but that its hue does often fade. This must surely cause a reflecting mind to ask himself how this can be. The color is so beautiful and useful to the artist that some effort should be made to prevent its total expulsion from his palette, and here we have an instance of the importance of chemical knowledge to the artist. It is impossible in this place to go into the question; it is however manifest if a pigment stands well at one time but not at another, that it must be mixed, in the latter case, with something which does not agree with it. Now this is true; from its composition Prussian blue is affected by anything which will change the state of oxidation in which part of its constituent iron is held. Terra verte, for example, is, or ought to be, an earth tinted with the protoxide of iron; if this is mixed with Prussian blue it will in time change the condition of the oxide of iron in the Prussian blue, and therefore its color. In concluding these remarks on pigments treated of in Mr. Muckley's book one feels great pleasure in being able to state that with the few exceptions noticed there is nothing incorrect, only one feels how terribly wanting it is in completeness when a thoroughly scientific treatment of the subject is required. One of the points which artists have to guard against is adulteration of pigments; now this is a thing of constant occurrence, where cheap colors are bought, but in this work nothing is said about this important matter. However well an artist may select his paints, impurities in one or two of them may upset all his calculations and render of no value a work which might, if sound, represent a considerable sum of money. From the present position of art in this country this is probably the most touching way of putting it. It would be well, in a future edition, if Mr. Muckley would attend to this, and give some simple methods by which the impurities could be detected. It is as important to the artist that he should understand the nature of the vehicles with which he paints as the composition of his pigments, and here one wishes that Mr. Muckley had gone more into detail, and that he had given reasons why such substances as maguilps, mastic, sugar of lead, etc., are so very objectionable. The reason why pictures crack is because two or more media are used which dry differently; if the vehicle employed is homogeneous there is no fear of cracking. Maguilp is made by mixing linseed oil with mastic varnish, and mastic varnish is gum mastic dissolved in turpentine. When these are mixed together the turpentine goes to the oil and leaves the mastic in a jelly-like condition; the whole mass is then rubbed up together, and in proportion as the mixture is more or less complete so will the vehicle be more or less liable to crack, because it is made up of substances which take different times in drying. All maguilps are bad; here Mr. Muckley is right, and he is also right in advising the use of amber varnish and of good copal varnish tempered with nut (better with poppy) oil. No better media can be used than these, but the picture must be painted from first to last with one of them, whichever the artist selects, but the amber is the best. Six years ago the then professor of chemistry at the Royal Academy urged Messrs. Winsor and Newton to get amber varnish made, and that firm did so, therefore amber varnish has been to be had for that space of time, and several artists of distinction, viz., Mr. Brett, Mr. Vicat Cole, R.A., and others, have painted with it to their entire satisfaction; nor have they complained that it is too dark to mix with their lighter colors. When a picture is perfectly hard which has been painted with this vehicle, no better varnish can be used, when required, than amber varnish properly applied, that is, in as thin a coat as possible. Mr. Muckley speaks of mastic varnish blooming, but he does not tell us why it does so. It is because the substance is hygroscopic, and taking up moisture is the cause of blooming, therefore it should never be used. All driers, as he says, are unnecessary, they are all ruinous to pictures; under certain conditions crystallizable driers crystallize out and make the picture spotty. It would have been much more satisfactory if Mr. Muckley had treated this part of his subject at greater length and with greater minuteness; it is evident that he is quite competent to do so. Copal is a name used by varnishmakers for several kinds of gum, and some of the cheap varnishes do not contain any of the better or harder gum. The kind used for artists' varnishes is what is termed a fossil gum, and is found largely at Zanzibar; it is almost, if not quite, as hard as amber, and almost intractable. The best copal varnishes sold by the best artist colormen are, as a rule, made from this gum, and can be obtained from them with confidence. It is however pleasing to learn that so conscientious and respectable a firm as Messrs. Mander Brothers of Wolverhampton have undertaken to manufacture vehicles "in accordance with the old formulæ supplied by the author." There is no need whatever to use sandrac, it is very brittle and unmanageable.

In the work before us "turpentine" is spoken of as being, in conjunction with colors, "detrimental to their permanence." Turpentine, which is distilled with water from coniferous trees, oxidizes and forms a resin. This it does most readily in the presence of moisture and sunlight. If then turpentine he kept free from moisture, in a well-corked bottle, in the dark, this will not happen. and the way to keep it free from moisture is to put into it lumps of quicklime or fused chloride of calcium; when so treated it may be used with safety. One does not lke to have so old a friend banished without saying a word in his defence. The suggestion made to use oil of lavender is a very good one, but it need not displace turpentine, but both must not be used together.

The conditions under which a painter commenced his education in former times were totally different from what they are now." It would be better for art if they were the same, though perhaps not better for art regarded as a trade. The paintings of the old masters certainly beat most of the modern works in this country, both in merit and durability. Mr. Muckley's remarks on this point are very good; one only wishes that he bad treated this part of his subject more fully.

The chapter on "Mixing and Nature of Colors" is not as complete as it should be, from the almost entire absence of chemical illustrations, which on such a subject are invaluable. One remark, however, which often occurs in this book is most admirable. "The painter should always make an effort to use as few colors as possible, and they should be of the most permanent kind."

On damage to oil-paintings by gas and damp, it is stated that painters' canvas is usually prepared by first covering one side of it with a coat of whiting, to which glue size has been added. This is hardly a correct statement of the method employed by the best firms. The canvas is treated with size rubbed in with long knives, in the jelly form, it is then scraped off as bare as possible. This is done to protect the canvas from the disintegrating effects of the oil used in the preparation of the surface, for oil oxidizes and speedily rots canvas, and therefore a coat of oil paint would not be, as stated, a protection to the back of prepared canvas: better use paraffin, which does not oxidize. Space will not allow a further notice of the concluding chapters of this work. One or two points, however, seem to require remark. "If darkening of a picture is due to some chemical action in the colors themselves, which is not unfrequcntly the case, the original condition of the work cannot be restored." If the darkening be due to the action of sulphuretted hydrogen or white lead, the whiteness can be restored by washing with peroxide of hydrogen.

In the directions given for painting the walls of the paintingroom it is advised to use Prussian blue, and the vehicle to he employed is spoken of as distemper color. Prussian blue is immediately decomposed by lime or chalk, and therefore cannot be used with these materials.

On the whole, one feels great pleasure in recommending this book as useful to art students. As has been before stated, it is matter for regret that parts of it have not been more fully treated, and at the same time it must be observed that, as regards scientific questions involved in the composition of pigments and on their action on one another, as well as the adulterations with which they are contaminated, the subject is almost wholly untouched, and we must look for some further treatise to illustrate and explain these points, either from Mr. Mucklcy or from some other author.