THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



354 



through a fine hair sieve into an earthenware jar; a number of these jars are 

 reoS and eaeh is filled to within a third of the top. The hme is allowed 

 to settle and when the water which rises over its surface is clear, it is poured 

 off This is repeated till there is no nihre water to pour off, and the Ume 

 remains in the jar of the consistence of the white paint commonly used and 

 [s ouite as smooth. It is now ready to be mixed for the in/onaco, which 

 consists as usual of two parts sand and one of lime Great pains are «ken m 

 Italy to find a suitable sand: it must be perfectly clean, sharp sand, the 

 erains of eoual size, and its colour favourable, as the mtonaco should not be 

 too dark 'the presence of any earthy particles in the plaster would mevit- 

 ably ruin the fresco : this accounts for the very careful preparation which all 

 the materials used undergo." , , , t t).,-= 



Professor Hess recommends avoiding the intermixture of plaster of 1 ans 

 in the mortar for the first rough coat (in the finer coats it is never emploj-ed 

 as a preparation for fresco) and advises o modcri-te use of small fliut pebbles. 

 The rough coat should not be too compactly laid on, as its porousness is 

 essential to the convenience of fresco painting. In like manner the last fiiier 

 coats should be lightly floated on to ensure their power of absorption. He 

 Droceeds • " The plaster for painting ou is composed of lime not in too caustic 

 a state and pure quartz sand. With regard to the Ume it should be wdl and 

 uniformly lianipulated, and should be entirely free from any small hard 

 lumps The sand should be very carefully washed to cleanse it from clayey 

 or saline particles, and should be afterwards dried in the open air. Sand 

 that is course or unequal m grain should be sifted ; thus tbe plaster will be 

 uniform in its texture. The proportion of sand to the lime is best learned 

 from experience, and must depend on the nature of the hme. If the plaster 

 contaius too much lime it becomes incrusted too soon, is too smooth m sur- 

 face and easily cracks ; if it contains too little it is not easily floated, the suc- 

 cessive patches (as the fresco proceeds) are not to be spread conveniently in 

 difficult situations, and the plaster is not so lasting. ,,.,,, 



" Before laying on the plaster, the dry rough coat is wetted with a large 

 brush again and again, till it will absorb no more. Particular circum- 

 stances, such as spongy bricks in the wall, humid or very dry weather 

 &c dictate the modes in which this operation is to be regulated. The plaster 

 should be laid on lightly and freely with a wooden hand-float ; in connecting 

 the successive patches some portions require however to be finished with an 

 iron trowel ; in this case care must be taken not to press too strongly, otlier- 

 wise rust spots might appear in the lime, and even cause portions of the 

 superadded painting to become detached. [A glass float seems to be prefer- 

 able where a wooden instrument is unfit.] The plaster should be about a 

 quarter of an inch in thickness. The surface of the last coat is then slightly 

 roughened to render it fitter for painting on. The wall thus prepared is to 

 be left a quarter or half an hour before beginning to paint. 



The colours enumerated by Professor Hess are the following. White : 

 lime "hich has either been long kept, or by repeated manipulations aud dry- 

 ing is rendered less caustic. Yellow : all kinds of ochres, terra di Sienna, 

 Red all kinds of burnt ochres, burnt terra di Sienna, [the brightest particles 

 selected at different stages of the process of buruing, furnish, according to 

 Director Cornelius, very brilliant reds,] oxides of iron, and lake-coloured 

 burnt vitriol. Brown ; umber, raw and burnt, and burnt terra vert. Black : 

 burnt Cologne earth, which when thus freed from its vegetable ingredients, 

 affords a pure black. Purple : burnt vitriol, cobalt blue, and lake-coloured 

 burnt vitriol. Green : Verona green (terra vert), cobalt green, and chrome 

 ereen Blue : ultramarine, cobalt, and tbe imitation of ultra-marme ; the last 

 h most safely used for flat tints, but does not always mix well with other 

 colours. These colours have been well tested, and for the most part admit 

 of being mixed in any way. Other more brilliant colours, such as chrome 

 yellow, vermilion, &c., have been tried in various ways, but have not yet in 

 every case, been found to stand. Colours prepared from animal and vegetable 

 substances cannot be used at all as the lime destroys them." Fresco-painters 

 observe that " great attention is necessary in the due preparation of tints on 

 the palette, for if tints are mixed as the work proceeds, the pamting when 

 dry will appear streaky ; when the colours are wet the differences are not so 

 perceptible." 



In additions to hog's hair tools, which, as before observed, are longer than 

 those used in oil painting, " small pencils of otter hair in quills are used. No 

 other hair resists the Ume, but becomes either burnt or curled. The palette 

 of the material and form before described, is covered with a light coloured 

 varnish to protect the tin from rust. Rain water (that has not passed 

 through an iron tube,) boiled or distilled water should be used from first to 

 last in all the operations of fresco-painting." 



Professor Hess continues :— " After tbe painter has laid in his general 

 colour, he should wait half an hour or an hour, accordingly as the colour 

 sets, before ho proceeds to more delicate modelUng. In these first opera- 

 tions he should avoid warm or powerful tints, as these can be added with 

 better effect as the work advances. After the second painting and another 

 shorter pause, the work is finished with thin glazings and washings. In this 

 mode the requisite degree of completion can be attained, provided the day- 

 light and the absorbing power of the plaster last. But if the touches of the 

 pencil remain wet on the surface, and are no longer sucked in instantane- 

 ously, the painter must cease to work, for henceforth the colour no longer 

 unites with the plaster, hut when dry will exhibit chalky spots. As this 

 moment of time approaches, the absorbing power increases, the wet brush 

 is sucked dry by mere contact with the wall, and the operation of painting 

 becomes more difiicult. It is therefore advisable to cease as soon as these 

 indications appear. . ia-ntuMt^- 



[October. 



" If the wall begins to show these symptoms too soon, for example in the 

 second painting, some time may be gained by moistening the surface with a 

 large brush, and trying to remove the crust or setting that has already begun 

 to take place ; but 'this remedv affords but a short respite. In the additions 

 to the painting on successive days, it is desirable to add the new plaster to 

 that part of the work which is not quite dry, for if added to dry portions the 

 edges sometimes exhibit spots. Various other effects sometimes take place 

 from causes that cannot be foreseen, and the remedies must be provided by 

 the ingenuity of the artist, as the case may require." 



The following extract from a letter addressed by Mr. Andrew WUson to 

 his son (in March last) will render the process of painting in fresco more in- 

 telligible ; but it is almost needless to observe, that in such details, the 

 practice of painters may vary considerably. . 



" I lately went to tbe royal palace (Genoa) to see the Signor Pasciano 

 paint a ceiling in fresco, llis tints had all been prepared before my amval ; 

 he had only two in pots, viz. pure lime and a very pale flesh tint. He had 

 no palette, but a table with a large slate for the top : on it he set round, 

 1. Terra vert. 2. Smalt. 3. VcrmiUon. 4. Yellow ochre. 5. Roman 

 ochre. 6. Darker ochre. 7. Venetian red. 8. Umber. 9. Burnt umber. 

 10 Black These colours were all pure, mixed only with water and rather 

 stiff put down with a palette knife, perhaps about an ounce, or two at most, 

 of each He mixed each tint as he wanted it, adding to each from the pot 

 of flesh tint or that of white. Near him lay a lump of umber, and on taking 

 up a brushful of colour he touched this with it ; the earth instantly absorbed 

 the water, and he was thus enabled to judge of the appearance which the 

 tint would present when dry. The painter used a resting stick with cotton 

 ou the top to prevent injury to the intonaco. The mtonaco being prepared 

 in the manner which I have described, the moment it would bear touching, 

 he set to work. The head was that of the Virgin ; he began with a pale 

 tint of yellow round the head for the glory, (the colour of the ground, 

 owing to the mixture of sand with the lime, it is to be remembered is a cool 

 middle tint,) he then laid in the head and neck with a pale flesh colour, and 

 the masses of drapery round the head and shoulders with a middle tint, and 

 with brown and black in the shadows. He next, with terra vert and white, 

 threw in the cool tints of the face j then with a pale tint of umber and 

 white modelled in the features, covered with the same tint where the hait 

 was to be seen, and with it also indicated the folds of the white veil. AU 

 this time he used the colours as thin as we do in water colours ; he touched 

 the mtonaco with great tenderness, and aUowed ten minutes to elapse before 

 touching the same spot a second time. He now brought his coloured study, 

 which stood on an easel, near him, and began to model the features, and to 

 throw in the shades with greater accuracy. He put colour in the cheeks and 

 put in the mouth slightly, then shaded the hair and drapery, deepening al- 

 ways with the same colours, which become darker and darker every time ■ 

 they are applied, as would be the esse on paper for instance. Having worked 

 for half an hour, he made a halt for ten minutes, during which time he oc- 

 cupied himself in mixing darker tints, and then began finishing, loading the 

 lights and using the colours much stiffer, and putting down his touches with 

 precision and firmness : he softened with a brush with a Uttle water in it. 

 Another rest of ten minutes : but by this time be had nearly fimshed the 

 head and shoulders of his figure, which being uniformly wet, looked exactly 

 like a picture in oil, and the colours seemed blended with equal facility. 

 Referring again to his oil study, he put in some few light touches in the 

 hair, again heightened generaUy in the lights, touched too into the darks, 

 threw a little white into the yeUow round the head, and this portion ot his 

 composition was finished, all in about an hour and a half. This was rapid 

 work, but you will obserAc that the artist rested four times so as to aUow 

 the wet to be sufficiently absorbed into the wall to aUow bun to repass over 



his work. , . xi_ . • 



" The artist now-required an addition to the mtonaco ; the tracing was 

 again lifted up to the ceiUng, and the space to be covered being niarked by 

 the painter, the process was repeated, and the body and arms of the Ma- 

 donna were finished before I left him at one o'clock." 



The following is an extract from a second letter. " Yesterday 1 went 

 again to see Pasciano, and I found that he had cut away from his tracing or 

 cartoon those parts which he had finished upon the ceiUng: in fact I now 

 found it cut into several portions, but always carefuUy divided by the outline 

 of figures, clouds or other objects. These pieces were in some instances a 

 good deal detached from each other, and were naUed to the plaster so as to 

 fold inwards or outwards for pouncing the outUnes. The intonaco had just 

 been fresh laid for the upper half of an angel supportmg the feet of the 

 Madonna: this was one of a group much larger than those surrounding the 

 glory and therefore requiring more colour and finish ; more than halt ol tne 

 figure too was in shadow, with a strong ray of light on the face and on one 

 of the arms : this was a good opportunity of observing the painter s ma- 

 nagement of shadow. Having gone over the outUne carefully with a steel 

 point, he waited till the intonaco became a little harder, and in the mean 

 time mixed up a few tints, he then commenced with a large brush and went 

 over the whole of the flesh : he next worked with a tint which served for 

 the general mass of sliadow, for the hair, and a slight marking out ot tne 

 features. He now put a little colour into the cheeks, mouth, nose and 

 hands, and all this time he touched as lightly as he possibly could, not to 

 wash up the intonaco. He then halted for ten minutes, looking at his oU 

 study, and watching the absorbtion of the moisture, and he called my at- 

 tention to his outline : none of it was effaced by this washing. 



" The intonaco would now bear the gentle pressure of his fingers, and 



