The purpose of this ink is, first, to cause a ma.s.s of oily, fatty substances to soak into the pores of the stone and also make certain portions of its surface fatty; and secondly, to resist acids according to requirement in such degree that the stone shall remain fat where needed, that thus the design, applied with this ink, shall be left untouched by acid.
I have remarked before that countless different mixtures can be made, most of which fulfill the purpose. But there enters the consideration that it must be an ink easy to use, that handsome work may be done by the artists with perfect ease.
Various mixtures answer this purpose very well, and I have found sometimes that men could work better with mixtures made by themselves than they could with those that I used for my own work. Perhaps this was a matter of imagination, or the real reason lay in the pen-cutting, it being well known that one man can use a pen that is absolutely worthless for another.
I myself have tested the values of some mixtures so thoroughly that I can declare almost positively that it will not be easy to find better ones for any purposes. I will describe these fully.
First of all, stone-ink is divided into two great cla.s.ses. One is thicker, being used for drawing on stone. The other is more fluid, being used for transfers.
The following mixtures of the first kind are the best:--
(1) White Wax 8 parts Soap 2 parts Lampblack 1 part
This ink does not really serve for writing or drawing on the stone, but is used mostly for coating those places that are to be protected from the etching fluid. If this ink is needed in a thickened form, the wax should be heated in an iron pan till it burns and the combustion should continue till one half of it is consumed. The longer it burns, the harder will be the remnant.
(2) White Wax 12 parts Tallow (Ox Fats) 4 parts Soap 4 parts Lampblack 1 part (3) Wax 12 parts Sh.e.l.lac 4 parts Soap 4 parts Lampblack 1 part (4) Tallow 8 parts Sh.e.l.lac 8 parts Soap 4 parts Lampblack 1 part (5) Wax 8 parts Sh.e.l.lac 4 parts Mastic 4 parts Soap 4 parts Lampblack 1 part (6) Wax 8 parts Tallow 4 parts Sh.e.l.lac 4 parts Soap 4 parts Lampblack 1 part (7) Wax and Gum quajak 12 parts Tallow 4 parts Soap 4 parts Lampbblack 1 part
The wax and gum are melted in equal proportions, the undissolved portion is discarded and of the mixture twelve parts is used as above.
(8) Wax 6 parts Sh.e.l.lac 4 parts Tallow 2 parts Mastic 3 parts Venetian turpentine 1 part Soap 4 parts Lampblack 1 part
There is no important difference between the inks in the seven last formulas. Those that contain sh.e.l.lac remain fluid a little longer but are harder to prepare. It is not necessary to be painfully minute about the proportions of the various materials, providing the proportions of soap and lampblack be correct. The soap is about one fifth and the lampblack about one twentieth part of the whole. If too much soap is used, the ink will dissolve more readily, but the solution will become slimy more quickly. Too much lampblack would make the ink run.
MAKING THE CHEMICAL INK
In making any of the inks mentioned, first divide the required quant.i.ty of soap into two equal parts. Put one part into an iron pan with the other substances, and heat till the ma.s.s begins to burn. Let it burn till almost one half is consumed. Then cover the pan with an iron lid, or place it very carefully into a basin of water to extinguish and cool the mixture.
One part of the soap is mixed in at once, that the combustion may make it mix well with the other substances. But it loses some of its strength and sates itself with carbonic acid, so that it is not quite so powerful as before to attack the fats. Therefore a second part is added after the combustion. Then the complete mixture is heated again, but only to a degree sufficient to melt the soap.
Now take up a bit of the ma.s.s with a clean knife and see if it is easily soluble in river or rain water. If the soap was good (something not always the case), the quant.i.ty named in the formulas always suffices. If it does not contain enough alkali, little pieces of soap must be added till the ma.s.s is soluble. Then the lampblack is added while the ma.s.s is being stirred without cessation.
The lampblack must be of the finest sort, and should be roasted and burned in a closed vessel until it ceases to give off any yellow smoke.
When everything has been stirred till the ma.s.s is nearly cold, it is kneaded into any desired shape, sticks being the best, and so saved for use.
The following remarks are to be noted especially:--
(1) The soap is to be the ordinary soap made from ox fat and lye. In the formulas its weight is calculated in fresh form, which, of course, includes considerable water. If the soap is very dry, less must be used.
Venetian or vegetable oil soap is not so good because the ink easily becomes slimy afterward when dissolved in water. It does not resist acids so well, either. If, however, the other kind is not to be had, or to be had only in poor quality, the Venetian soap will do. It will be necessary merely to make frequent fresh solutions in water of the ink.
(2) Lampblack is not the only substance available for giving color to the ink. Vermilion, red chalk, indigo, blue lake of logwood, and several other colors can be used, so long as they do not consist of acids or other salts, and thus have properties that could alter the nature of the soap. The finer kinds of ordinary lampblack can be used without burning, but then a part of the soap always is rendered inactive, because the lampblack usually contains a considerable quant.i.ty of inflammable wood acid which unites with the alkali, neutralizes it, and thus destroys its effectiveness against fats. Therefore, if it is not roasted beforehand, it may be necessary to mix more soap with the ink after it is made, and this does not completely remedy the trouble. Lampblack can be purified by rubbing down with strong lye and then boiling in sufficient water till no trace of alkali remains, if roasting and burning be undesirable for any reason.
Better even than this purified lampblack is one that one makes for himself from ox or other animal fat, from wax, or better still, from a mixture of ox fat and resin. The fat is melted and poured into an earthen lamp similar to those used for city lighting, with a cotton wick. The lamp is lit and placed under a plate of iron or bra.s.s, so that the smoke must settle on it. The plate must be close to the flame. The soot is sc.r.a.ped off from time to time and dropped into a gla.s.s, which is kept covered. This process continues, the lamp being refilled till one has the desired quant.i.ty. This soot is very fine and bland, and so good that one can do more with an ounce of it than with three ounces of the ordinary kind. The ink made from it is extraordinarily fine and good.
It is to be noted in conclusion that the more soot is used, the blacker will be the ink, but the coa.r.s.er will be the work, because the ink will have the tendency to spread. The less soot is used, the finer will be the work; but it is not easy then to see what one is doing or to judge if the design is strong enough. The quant.i.ties given in the formulas appear to me to be the best, especially if the self-manufactured soot is used.
(3) To dissolve the ink, rain water or pure soft river water is best.
The rain water must not be very old or stale, otherwise the solution will get slimy.
(4) The severe combustion is not vital for making the ink, but helps very much in making it easy to use.
(5) When sh.e.l.lac is part of the mixture, it is vital to burn the ma.s.s well, as only thus will sh.e.l.lac dissolve properly.
Sh.e.l.lac, which is made in China and East India from an insect belonging to the bee family, will melt under moderate heat, but will not dissolve in any animal fat or oil unless it has previously lost its inherent acid, which occurs only under combustion. If sh.e.l.lac is melted with oil or fat, it covers the bottom of the vessel in the beginning. With heat increased till it causes combustion, it begins to swell, rises to the surface, and at last covers the surface in the form of a spongy ma.s.s. If the heat still increases, it begins to dissolve into foam. Then it is time to remove the ma.s.s from the fire and to cover it with a tight lid, that the flame may be extinguished.
If sh.e.l.lac has been once melted and has hardened, it dissolves only slowly even under severe combustion. It is better, therefore, to bring the other substances to combustion first, and then to mix the sh.e.l.lac in small portions, which will dissolve much more readily because they will be attacked by the great heat in the moment of melting and will not have time to swell first and get hard.
As soon as the ma.s.s has cooled a little, the second part of soap is added, and the whole heated, without burning, merely enough to melt the soap.
(6) None of these mixtures can be kept well any length of time in fluid form, that is, dissolved in water, because it becomes slimy after a very few days, sometimes sooner. It can be liquefied again by mixing with water, but not without affecting its durability. Therefore the ink must be stored dry, in which form it lasts for years without change. When required, a small quant.i.ty, about the size of two peas, is rubbed down in a very clean small earthen or porcelain vessel, such as a saucer.
Those mixtures that contain tallow rub the easiest. The others, containing harder substances, require more pressure. The ink should be spread evenly over the bottom of the vessel. Then a coffee-spoonful of rain or other soft water is poured in, and the mixture is rubbed with the finger till the solution is perfect. Then it is put into a small, very clean pot of gla.s.s or porcelain and is ready for use.
(7) A great deal depends on the proper quant.i.ty of water. A good ink must be completely dissolved, with no solid particles left. It should be about as fluid as a good, fat milk or vegetable oil. If it is too thick, it makes the work difficult. If it is too thin, it will not withstand the etching fluid. A few experiments will teach the proper proportions.
Even a good ink will make poor lines if it is laid on too thinly and not firmly enough. This, however, is due to the artist"s lack of skill or to defective pens, of which I will treat hereafter.
With this quant.i.ty of ink it is possible to work for a whole day. Thus each day fresh ink can be mixed; and it is to be noted that the vessels must be cleansed scrupulously that no trace of the previous day"s ink be left in them. The ink will dry during the work, and as soon as this begins to interfere with its use, one or two drops of water will thin it again sufficiently.
This is about all that need be said about the chemical fatty or alkaline stone-ink in general. Particular remarks will be found in the description of its use for particular methods.
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HARD BORAX INK
Besides the inks described, it is well to make the following and keep it in stock for uses whose great value will be explained later.
Sh.e.l.lac 4 parts Borax 1 part Water 16 parts
Borax and sh.e.l.lac must be put into a clean pot filled two thirds with water and boiled for an hour. As the water boils away it must be replaced. When the sh.e.l.lac has been mostly dissolved, the ma.s.s is removed from the fire, cooled, and filtered through a clean cloth to separate the undissolved portions of the sh.e.l.lac.
This solution can be kept for years in a tightly closed gla.s.s. To color it, a portion is to be cooked in a copper or iron ladle till it is thick as honey. Fine lampblack or vermilion is stirred in till the ma.s.s is thoroughly united. Then water is added, and the composition boiled again till it is a perfect solution. This black or red ink is first-cla.s.s and can be kept well in tightly closed gla.s.s.
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FLUID INK
Herr Andre, in Offenbach, uses an ink which has the useful property of remaining good for years in fluid form. I do not find it so good for the very finest work as those I have described, but for music and script it is excellent. It consists of:--
12 parts sh.e.l.lac 4 parts mastic 1 part pure ox-fat soap 1 part purified crystallized soda 1 part lampblack
This is mixed with water and boiled in a clean vessel, being constantly stirred till it is dissolved. Then the boiling is continued till the water has disappeared almost entirely. Fresh water is added and the boiling continued till everything has dissolved anew. Then the mixture is filtered through a cloth and kept in a vessel where it is secure against dust. If it is seen on cooling that it is too thick it can be thinned easily with water. Also, when it dries during use it can be liquefied by adding water, unless dust has entered it.
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