33S 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[No 



v. 



Pictures painted with oil only, or with common magjlp, consist of a succes- 

 iionof skins or layers of paint, more or less cut off from mutual intercourse ; 

 but the cero-resinous medium keeps the whole substance in a constant state 

 of intercommunicative moisture during the progress of the work. The 

 painter can pursue his operations, without delay, to any stage he may think 

 proper; he may also return to them at pleasure; and he will find himself 

 relieved from the necessity of such a preparative as " oiling out," an in- 

 jurious and disagreeable practice, often called for by the greasy oozings 

 tlirough the surface or outer skin of the oil picture. It may also be remark- 

 ed that the scrapings, glazings in, and rubbings off for texture, which are so 

 often resorted to where oil alone has been used, are wholly unnecessary in 

 this system, which, by humouring the vehicle to the required consistence, 

 yields all the means for a varied manipulation that can be desired.^ 



Encaustic. — When the picture is completed, a short time being allowed 

 for the evaporation of any excess of essential oil which may remain in those 

 portions of tlie work which have been recently loaded with colour, it should 

 be gradually moved towards and held in front of a fire until the surface has 

 obtained an equal gloss, care being taken that it does not fry by too sudden 

 or close an approximation ; it must then i)e withdrawn to set and cool ; 

 after wliich it must be rubbed with fine linen cloths or with silk until a 

 pohsh is produced. If the picture be large, a cauterium, or chafing-dish, 

 may he moved in front of it at a careful distance (from 2 feet to 18 inches or 

 a foot, but not nearer), in order to obtain the required gloss. Should the 

 picture have been painted upon millboard or panel, the evaporation of the 

 essential oil must necessarily take place from the surface only ; the capacity 

 of the picture for retaining heat being thus greatly increased, tbe latter will 

 act, if the encaustic or " burning in" process, be performed gradually and 

 slowly upon the resin, as well as the wax and oil, and effect a thorough fu- 

 sion of the whole medium, which will result in a most brilliant and durable 

 enamel, more resembling a vitrified than a waxed surface. The more perfect 

 the desiccation, the more perfect and durable will be tbe gloss. Tbe reason 

 why encaustic surfaces frequently become dull is, that the gloss is produced 

 before the essence has entirely evaporated, the after-evaporation through the 

 wax enamel reproducing the flat and porous surface. " Its lustre," says 

 Professor Tingry, " is equal to that of varnish, without having any of its in- 

 conveniences. A wax surface stands shocks, a varnished one does not. If 

 any accident alters the polish of wax, rub it with a piece of fine cork." To 

 clean an encaustic picture, M. Durosiez gives the following directions ; — 

 " Remove the dust, wash it well with alcohol and water, then with pure 

 water, dry it, expose it to heat (In the mode described), and polish with 

 cloths as at first." The encaustic surface has more atmosphere than very 

 new varnish," and is sufficiently transparent to display the deepest shadows 

 to advantage; it does not require periodical additions, like fresh varnishings; 

 and it is not subject to chill, like most of tbe essential oil solutions of the 

 resins. " Encaustic pictures," says Montabert,' "never alter; they can be 

 retouched ; they are luminous and transparent, and possess all the excellen- 

 cies of oil-painting, combined with greater durability."' 



As an addendum to the description of the process, a few remarks on the 

 materials of which it consists may not, perhaps, be thought unnecessary. Oil 

 of Turpentine being the most available essence in this country, and answer- 

 ing the requisite artistic purposes quite as well as either rosemary or laven- 

 der, it may not be amiss to retain it for the process. The best bleached 

 bees-wax that can be procured is another required ingredient. Pure wax 

 from the comb, bleached by exposure to the light,' is to be preferred to the 

 shop white wax, as the latter is usually adulterated with tallow. Wax is 

 said by many to run when used in pictures, and by others to be subject to 

 crack. Professor Brande, however, informs us in his " Chemistry" that this 

 substance will not melt under 154^^ Fahrenheit, adegree of beat scarcely ever 

 attained by the sun in this country; this statement, which differs but slightly 

 from that of other eminent chemists, ought to satisfy the most suspicious 

 that the confidence placed in wax by the Greeks, Romans, and Egyptians, 

 denizens of far hotter climates than ours, was not thai of ignorance. Be- 

 sides, when in combination with other matters, wax is so notorious for its 

 powers of adhesion, that a vastly increased degree of heat would be required 

 to fuse it when so circumstanced. I have several times exposed sketches, 

 painted with this cero-resinous vehicle united to colours ground in oil,'to a 

 stove heat of ICO° Fahrenheit after tbe essential oil had entirely evaporated, 

 without the slightest running of the surfaces. And in forcing the heat still 



5 If the addition of a little oil or extra turpentine essence be required, and the magylp. 

 ing property be overpowered, recourse must be had to the palelte tins. 



Dr. Bachoffner, in allusion to Sir Humphry Davy'a having? found the colours of the an- 

 cients (at Pompeii) to be similar to those now in use, thinlcs " that modern vehicles are 

 at fault." — * Chemistry applied to the Arts." 



6 See Boschini's remarl<s on varnish glare, and the aversion in which the Venetians 

 held it, in the *' Third Report of Commission of Fine Arts." 



' "Traits complet de la Peinture." 



fl For a wax v.irnish : "Take three parts white wax and one part resin; melt toge- 

 ther; apply over the picture, and polish with cloths."— * Antologia Romana.* 



3 The blocks of yellow wax may be bleached as follows : Cut them into shavings upon 

 a carpenter's plane inverted; and then expose them to the sun in an unsmoky .atmo- 

 sphere, occnsionally turning over and moistening them with clenn water. In the steady 

 and potent light of Italy, the bleaching operation is completed in three or four days, as I 

 have many times witnessed; but in our variable climate it cannot be etfectad without 

 more time and trouble. The brown wax of commerce is frequently adulterated with 

 common resin. The dark. coloured old combs are almost unbleachable, and their sub- 

 stance is of a less tenacious or waxy character, as it is mixed with hie bread and oth«r 

 impurities . Fine bees-wax may always be obtiined of Mr. Milton, the eminent apiarian, 

 111 Wejmauth-slreet, Portland-place. 



higher upon a layer of white-lead ground in oil added to tbe vehicle, the 

 white became very slightly tinged with yellow (from the partial combustion 

 of the oil, as I afterwards proved) without any other change whatever.'" As 

 to tbe disposition of wax to crack in pictures, it may be observed that unless 

 it be employed in some layers and excluded from others, cracking cannot 

 possibly ensue. Since, however, there are no two substances in the painter's 

 mali'riel which are characterized by similar dispositions to contract and ex- 

 pand, extreme caution should be adopted in the juxta-position of differently 

 constituted vehicles in the several layers of a picture. Varnish overunhard- 

 ened oil, drying oil over the same, or wax over any of the three, would be 

 very likely to produce cracking. Dr. Roux says tiiat "wax does not con- 

 tract like the unctuous oils ;"'• and the Italians consider that new tempera 

 as well as oil-paintings are subject to crack in extremely dry seasons, but 

 that wax rests undisturbed. Among tbe resins suitable to this process there 

 is abundant choice. Damara is a favourite on the continent. It is very 

 clear and bright, and does not crack when spread alone as an essence varnish 

 over a wax picture. Mastic, which has a little more colour, has long been a 

 favourite with painters, but it is very subject to chill (a failing which has 

 been attributed to unsound watery tears'^) when made with volatile only. 

 Correggio and tbe Lombard painters are said by Armeuini to have dissolved 

 it in fixed oil for a glazing vehicle or varnish. Sandrac was a favourite with 

 the old masters ; but I found it work very harshly without fixed oil. Elerai 

 is anotlicr continental favourite. It is slightly coloured, but is said to be 

 tough in varnish. (Aiken.) Anirae is difficult to dissolve; " it is more brit- 

 tle and less solid than copal. (Tingry.) The fluid resins, Venice and Chio 

 turpentines, with Canada and Capivi balsams, may any of them be used to 

 advantage in this process, due consideration being had to the excess of es- 

 sential oil which they contain. '" Tlie solution of the harder resins seems 

 to have been better understood in former times. To dissolve copal effectually 

 has ever been considered a difficult task; and perhaps a greater value has 

 been placed on tbe resin on that account, Tbe power of wax in consolidat- 

 ing the feeblest resins seems to place every requisite means at our command 

 without undue labour or difficulty. And yet the superior qualities of copal, 

 its toughness, its brilliancy, its consistence, and its durability, single it out 

 as the most desirable of all resins to bring into subjection. Bonanni, Tingry, 

 &c., &c., have devoted much time and skill to its solution, and have succeed- 

 ed variously. Oil of turpentine, which Tingry pronounces (because it is a 

 resinous essence) the most perfect solvent for resinous substances, and espe- 

 cially for copal, requires several months exposure to light in order to imbue 

 it with the requisite powers. The essence having attained these qualities, 

 will, when made hot, and in a warm room, take up the powdered resin, if 

 carefully sprinkled into it and stirred up at the same time. If the essence 

 be new, tbe solution is almost impracticable. When copal has been fused 

 and thrown into cold water before levigation, it dissolves more readily. It 

 has sometimes been fused a second time before solution, but this is an opera- 

 tion which must have a powerful effect on its best qualities, and it is to be 

 hoped that tbe least injurious mode may be generally adopted. The oils of 

 rosemary and lavender have often been successful where oil of turpentine of 

 a sufficient age has not been available. If the caoutchouc portion (so called) 

 of the resin continue to float in transparent masses after tbe essence has 

 cooled, time and light only can perfect the union. Tbe fluid resins readily 

 take up an eighth of tlieir weight of copal. I could never effect a stronger 

 solution with them ; but with three ounces of turpentine oil alone I have 

 completely dissolved an ounce of tbe pale copal unfused ; a proportion which 

 is quite strong enough for any useful purpose. One ounce of copal in eight 

 ounces of essence is the usual proportion in Tingry ; but one in three or four 

 is necessary to make a good cero-resinous magylp. I may observe that the 

 above solution of one to three dried very rapidly ; and that it possessed such 

 a degree of toughness and flexibility that five stout coats of it spread on a 

 broad strip of letter paper, and hardened, exhibited not the slightest symptom 

 of cracking when closely wrapped round so small an object as a common lead 

 pencil. ]f everv' painter desirous of possessing real copal varnish would 

 place a quart of oil of turpentine in his window, every three or four months, 

 in a clear glass bottle, leaving an interval of one or two inches between the 

 cork and the essence, removing each bottle as it became fit for use (in eight 

 or twelve months as it might happen), he would have every chance of con- 

 tinued supplies of the varnish for his studio ; since a pestle and mortar, a 

 common brown mug to hold the essence, and an Argand chemist's lamp to 

 receive the mug, constitute all the apparatus requisite to perform the opera- 

 tion both with precisian and safety. 



WnLiAM Linton. 

 7, Lodge-place, Regent's Park, August, 1846. 



» o Cenninl and Baldinucci give recipes for cements of wax and resin only for brokeo 

 marbles, in which the wax is proportioned to the resin as three to one. 



1 1 See the Third Report. 



12 J. Schetfer's " Graphice," Norimbergo, lGli9. 



1 a In applying these balsams and turpentines to pictures it has been advised to eva- 

 porate by heat the excess of essential oil which renders them fluid at the common tem 

 perfilure of the air, and to re-dissolve them in some more evaporable essence. An nn- 

 drying principle may be productive of as mucU mischief in a resinous as in an oleaginous 

 vehicle. 



