Secrets of Glass Manufactory - Compositions to Imitate Precious Stones, called French Paste

Secrets Concerning Colors and Painting
§ I.  Paint In Varnish On Wood
§ 2. Paint On Paper
§ 3. Compositions For Limners
§ 4. Make Transparent Color
§ 5. Compositions to Dye Leather
§ 6. Color or Varnish Copperplate Prints
§ 7. For Painting on Glass
§ 8. Color Preparation for Oil, Water, and Crayon
       Marble and Jasper Paper
       Methods to Clean Paintings
       Making Good Crayons
       Directions for Coloring Prints
       Directions for Painting in Oil
§ 9.  Preparation of Lapis Lazuli to Make Ultramarine

    Take the bulk of a nut of white wax, melt it, and add to it the size of a musket ball of ceruse of Venice.-- When both are incorporated, form this composition into small sticks. With them rub your piece of steel, or iron, after having previously warmed it sufficiently to melt the wax, which spread well over it with a feather. When the wax is cold, trace whatever you will on it, and pass afterwards, on the lines you have drawn, the following water.

II.  A mordant water to engrave on steel.

    I. Take the strongest verjuice you can find; alum in powder, and a little dried salt, pulverized.  Mix all together till perfectly dissolved: then pass some of that water on the lines of your drawing, repeating the same till it is sufficiently deep engraved.
    2. Or else take verdigrease, strong vinegar, ammoniac and common salts, and copperas, equal parts.  Set all together a boiling for a quarter of an hour; then strain it through a rag, and run some of that water on your plate.  In about half an hour afterwards it will be perfectly engraved.
    3. Callott's varnish, of which the composition shall be found hereafter, in the Chapter on Varnishes, is an admirable composition to lay on the plate you propose to engrave.

III.  To engrave with aquafortis, so that the work may appear like a basso relievo.

    Take equal parts of vermillion and black lead, two or three grains of mastich, in drops.  Grind them all together on marble, with linseed oil; then put this composition into a shell.  Next to this operation, cut some soft quills, and let your steel or iron be well polished.  Try first whether your colour runs sufficiently with you pens; and if it should not, you must add a little more oil to it, so as to have your pen mark freely with it, as if you were writing with ink on paper.  Then rub well your plate of steel with wood ashes, to clean and ungrease it; after which wipe it with a clean rag, and draw your design upon it with your pen, prepared as before, and dipped into your liquor. If you want to draw birds, or other animals, you  must only draw the outlines of them with your pen, then fill up the inside of those lines with a hair pencil; that is to say, you will cover all the space contained between the first outlines drawn with the pen, with the same colour, which you will lay with a brush, to preserve all that part against the mordacity of the aquafortis.  When that is done, let your work dry for a day or two; and when dried, take some fire made with charcoal into a chafing dish, and hake over it your colour by degrees, till it becomes quite brown.  Take care notwithstanding not to burn it, for fear you should scale it when you come to scratch, with the point of a needle, those etchings, or places, which you want to be engraved with the following aquafortis.

IV.  Aquafortis for engraving.

    Take verdigrease, roch alum, Roman vitriol, and common salt of each three ounce; pound it into a very fine powder. Have a new pipkin, put a little more than a quart of water, and your drugs, all together.  Let them thus infuse a couple of hours; then place them over a charcoal fire, and when the water has a little simmered, take the pot from off the fire and let it cool, that you may dip your hand in without scalding.  Then have an earthen cup, with which you take off that water, and pour it over the work you meant to engrave; so that it may run freely over all the places which are to be marked, and then off into a pan placed under to receive it.  Continue thus to water your works for three quarters of an hour.  Then you will pour upon it clear pump water, to wash off the mud which the aquafortis shall have occasioned.  You are then to try with a needle the depth of the lines of your engraving and, if not at your liking, you must begin again watering it as before.  The only care you are to have is, that your liquor should not be too warm; for then it would spoil the work.  It is better it use it lukewarm only, and be longer at it.

V. To engrave on brass, or copper, with aquafortis.

    You must put in your colour more mastich in drops, and bake it also rather more over the fire after it is laid on your plate, so that it should almost turn black.  And if it be a flat work, as generally are all those on copper plates, you must raise around it a border of wax to prevent the aquafortis, which you are to pour on it, from running off, and which is to be a separating aquafortis, with which you cover the plate to the thickness of a crown piece.  After it has been thus left covered with that aquafortis for a little while, this becomes green; then is the time to throw it away, and to pour in its place some pump water; when you will examine whether the lines be sufficiently deep or not.  If not, pour again fresh aquafortis on your plate, and thus you obtain your works of basso-relievo by contrary; that is to say, raised grounds.  You may thus engrave all sorts of works.

VI.  To engrave prints by aquafortis.

    Take some ceruse, grind it well with clear pump water and size it with isinglass.  Lay this composition with a coarse brush, or pencil, on the plate which you want to engrave.   When it is dry, draw on it whatever design you please.  Or, if you want to counterproof a copper-plate print, blacken all the back of your print, and placing that blackened part on your plate, prepared as before, go over all the strokes of your print, with a smooth ivory or wooden point, which will stamp the black of the print, in all those places, on the plate.  Then you will go again over all the black strokes which are laid on your plate, with a pen and ink; and taking afterwards a steel point, very fine and well tempered, you will etch your plate with it, in following all the strokes marked on it, and pour aquafortis, as before directed.

VII.  The method of engraving with aquafortis.

1.  You must have a very will polished plate, and perfectly clean.  Set it to warm over a chafing dish, in which there is a charcoal fire.  While on it cover it with a varnish, either dry or liquid, for there are two sorts.  Then you blacken that varnish with the flame of a candle, over which you pass and repass the plate on the varnished side.

2.  This being done, you have no more to do than to chalk your design on that plate, which is infinitely more easy than to engrave with the graver.  For if you rub the back part of your drawing with some sanguine stone (red chalk) or any thing else, and lay it afterwards on your plate, to trace it with a point, the sanguine which is on the back of the draught will easily set off on the varnish.  So that you may follow afterwards all the lines of the design, and be infinitely more correct in all the turns, and the expression of the figures. T This is the reason why all the painters who have their own works engraved, take the trouble of drawing also the outlines of their figures, that the spirit and beauty of the design may be preserved.  Indeed it must be confessed, that we always discover a great deal more art in those pieces which are engraved with aquafortis, than there is found in them that are done by the graver.  And, even in many of these, the aquafortis is often employed to sketch lightly the contours, or outlines of the figures, and to have them more correct.

3. True it is, that it is sometimes found necessary to touch a little over with the graver, certain parts which are not strong enough, or that the aquafortis has not eaten in sufficiently.  For it is not easy, in a great plate, to get all the several parts so proportionally, a propos, eaten in, as there should be nothing to find fault with.

4.  It is not enough for an engraver to work with the point of his needle, or scooper, in all the different places of his work, with the strength and delicacy necessary to make appear, as he wants them to be, the most remote and nearest parts.  It is again requisite that he should take care, when he comes to put the aquafortis on his plate, it should not bite equally everywhere.  This is prevented as follows, by a mixture of oil and tallow, which you will drop into it from a lighted candle.

5.  To this effect he must have a framed wooden board, overlaid with wax, on which he fixes his plate a little slant way, then pours aquafortis on it, so that it may only pass over it, and run into and earthen pan, placed under to receive it. Therefore he takes care to examine when those parts, which are not to be so deeply eaten in, have received a sufficient quantity of aquafortis; in which case, taking off his plate, he washes it with pump water, by pouring it only over, dries it gently before the fire, then covers the most remote parts, and them which he wants to preserve weakest, with the above mentioned mixture of oil and tallow, that the aquafortis should not act anymore on those places.-- This, covering at several times, and as much as he pleases, such places of his plate as he wants to keep not so strong as others, it results that the figures which are forwards in the picture, are constantly every time washed with the aquafortis which eats in the, till he sees they are sufficiently engraved, and according to the degree of strength which he is desirous of giving them.

6.  That sort of aquafortis we have mentioned and described in this chapter, at the article of the water for engraving on iron, and which is composed with verdigrease, vinegar, common and ammoniac salts and copperas, is also made use of to engrave on copper, in pouring it on the plates, covered either with hard or soft varnish, and scratched or etched, agreeably to the design you intent to engrave on them.

7.  As for what concerns the refiner's aquafortis, commonly called white water, it is never used but upon the soft varnish, and never as the former, which is called green water, by pouring it only over the plate, and letting it run off into a pan under it.  A border of wax must be made round the plate, on which, this being laid flat upon a table, some of that white water is poured, after having previously tempered it more or less with a proportional quantity of common water, which is called pickling.

VIII.  To engrave on wood.

    You begin by preparing a board, according to the size and thickness you want it, and finely polished on the site it is to be engraved.  The sort of wood which is generally chosen for such a purpose, is either pear tree or box.  And of the two, this last is even still preferable, both on account of its being of a superior hardness, and also less liable to be worm eaten.  On that board you draw first your design, such as you want it to appear in printing.  They who have not the talent of drawing, as there are a great number who make use of the very drawing you give them, which they paste on their board, by the right side, with a paste made of good flour, water, and a litter vinegar.  You must take care that all the strokes of the drawing should touch well, and stick on the wood; and when the paper is very dry, wet it gently, and with the tip of your finger rub it off by degrees, so that the strokes only of the drawing should remain on your board, as if you had drawn it with ink and a pen.  These strokes or lines show all that you are to spare or preserve; all the rest you are to cut off and sink down with delicacy, by means of a sharp and well tempered penknife, small chisel, or gouet, according to the size and delicacy of the work, for you have no need of any other tool.

IX.  To engrave on copper with the graver.

1.  When the plate, which is to be of red copper, is well polished, you draw your design on it with either the black lead stone or a steel point.  When that is done you have no further need of any thing but a sharp and well tempered graver to cut it in, and give more or less strength to certain parts, according to the subject, and the fine figures you execute.

2.  You must also have a certain tool of six inches long, or thereabouts, one of the ends of which, called a scraper, is mad in the form of a triangle, sharp on each edge, with which you scrape on the copper when you want it.  The other end, called a burnisher, has very much the shape of a fowl's hear, a little prolonged by the point, round and slender.  This serves to polish the copper, to meant the faults, and soften the strokes.

3.  In order to form a better judgment of your work you must now and then as you proceed on, make use of a stump, made with the piece of an old hat rolled up and blackened, with which you rub your plate. on the place you are working, which fills the strokes with black, and makes you see better the effect of your work as you go.  You must be provided likewise with a leather cushion, on which you lay your plate while you engrave it.

	Web old-crafts.com