All colors which we intend to use for marbling must be bound to bodies absolutely insoluble in water; it is therefore a mistake to say, that the colors dissolve in water. You may grind the color on a marble slab or in a machine as long as you please, but you will only obtain a great degree of fineness of the bodies but never a dissolution of the same.
Each body possesses its limit of divisibility; in amorphous bodies the high divisibility is but natural, but in crystalline bodies this division must be produced by grinding or washing.
The gall does not combine with these bodies, nor does it penetrate them, but only clings to them loosely. It can be readily removed in case the colors should be rendered useless by the addition of too much gall. The color is allowed to precipitate in the bottle and the water standing above is poured off, fresh water is added and this manipulation is repeated several times.
The gall which surrounds every particle of color forms, as it were, the support of it and adapts it to float upon the size.
Bodiless colors, which give a complete solution with water will run into each other on being thrown on the size and will flow from the paper when it is lifted off. The insolubility of the color bodies therefore prevents them from running although they are disarranged on the size in drawing and although one color may be compressed or expanded by a second, yet they all remain separate without mixing, except, perhaps, that the shade of the first color becomes more intense, because its color particles are pushed together by the more violent expansion of the second color.
From this it will be seen that the colors, to be useful for our purposes, must be thoroughly insoluble. The gall is added during the process of grinding the color, so that the particles of colors are fully surrounded by the gall. The gall has an excellent effect on the colors but it also can act very injuriously if the necessary precautions are not taken. Carelessness is mostly the reason that the edges do not possess the demanded l.u.s.tre of color and why they appear pale, as the marbler often uses the gall too soon when he notices the smallest obstacle, (due in most cases to the size.) It is therefore not astonishing that brilliant comb or peac.o.c.k-edges are so rarely seen.
It is an obstacle to marbling, that the gall mixes so easily with the size. It often happens that the gall spoils the size before an edge was ever produced on it. This happens especially when the size on which the colors are prepared according to the old method, is too thick. The size is frequently soiled and spoiled when the colors are prepared, because the colors can not be perfectly drawn off on thick size. There will always remain some particles which will not only soil the size but impregnate it with gall, and which will cause the entire uselessness of size and color.
A very consistent size will make the preparation of colors extremely difficult, as they need a double quant.i.ty of gall for the purpose of spreading out. If there is but one color used, the preparation on such a size would be possible without spoiling it, but with four colors this is entirely impossible because the repeated drawing off of the colors, which always leaves particles behind, will, by and by, impregnate the size so that when the fourth color is prepared the first will not spread out any further.
The more the impregnation of the gall and size increases, the power of expansion of the colors decreases and this continues until both materials are useless.
It is therefore advisable, as I have already stated, in the chapter upon the varieties of sizes that the colors should be prepared separately on a small part of size to determine the correct consistency of the latter and to prohibit the whole size being soiled.
The gall should be kept in a small bottle containing about 1/10 quart with a perforated stopper from which a small tube protrudes and from which the gall can be added to the colors in drops.
Although the preparation of the color in this way takes more time, this trouble is amply repaid by the result.
Fatty bodies are injurious to the size, therefore they must be carefully avoided because they have the same effect as the gall, they form, although not insoluble in water, a combination with the size and prohibit the colors from spreading out. Fatty bodies can be transferred by glutinous fluids into a state of the most minute division and they then form emulsions.
Natural emulsions are milk, the yolk of egg, and the milky saps of plants. For this reason, in many establishments raw milk is used as a propelling medium for hair-veined edges.
There are also fatty bodies which, in an artificial way, form an emulsion even with water; for instance, almond, poppy and hemp, if they are ground to a pulp with a little water yield a milky mixture. All these emulsions artificial as well as natural, can be employed as expanding mediums and give better results for marbling than petroleum or naptha.
Substances Acting Similarly to Gall.
SUBSTANCES ACTING SIMILARLY TO GALL.
There are rosins which are soluble in ammonia or borax. These solutions possess properties similar to gall and either can be used as an expanding medium or as an addition to colors. Different experiments with these solutions gave very good results.
To produce them pour a quart of water into a vessel, warm, add 2/5 of an ounce of sh.e.l.lac or rosin and a 1/100 part of a quart of ammonia or 2/5 of an ounce of borax so that the rosin becomes dissolved, and then bring the mixture to a boiling temperature.
Ammonia dissolves the rosins much more quickly and thoroughly than borax, but the solution in ammonia has the property of gelatinizing the colors after they have remained standing a short time. They therefore can only be used in a greatly diluted condition. The borax solution, on the other hand, has no such effect; not even the concentrated solution.
I mention these two solutions especially, to instigate further investigations.
SPRINKLING WATER.
SPRINKLING WATER.
Sprinkling water is one of the newer discoveries in the art of marbling and deserves full consideration on account of its good properties. Its advantages consist in this, that it produces circular forms upon the size and has a greater expanding power than gall.
Sprinkling water is used for hair-veined edges and as an addition to the ground color in marbling.
To prepare it take 1-1/2 ounces of Venetian soap, finely chipped, place them in a pot with a quart of alcohol, warm up some water in a second and large vessel in which the pot containing the alcohol and soap is put, bring the whole to boiling, when the soap will be entirely dissolved in the alcohol. Keep a quintuple quant.i.ty of water in readiness into which the solution of soap is poured and stir well, the sprinkling water is then ready for use. The solution of soap in alcohol is carried out in a water-bath to avoid the ignition of the volatile vapors which are generated by this process. The alcohol prevents the foaming of the soap, the soft water the curdling.
The solution when ready is to be kept in a closed bottle.
Generally to the colors which are used for hair-veined edges and marble more gall is added than to those used for drawn edges. It is, therefore, easily understood that with these, a more intensively acting expanding medium must be used to spread out the strong colors into veins.
The sprinkling water is here of great service, because, although ox-gall in its pure state possesses a sufficient expanding power it is here more desirable to produce beauty of forms. In this respect the gall is much inferior to sprinkling water, the former producing all kinds of forms, the latter only beautifully round and oval ones.
For marbling, the ground color is prepared with gall so far, until it slightly pushes the other colors aside and then, by and by, so much sprinkling water is added until the desired expanding power is reached.
Every ground color which is prepared with sprinkling water spoils on standing two or three days becoming slimy and viscous, and, for economy"s sake, not more color should be prepared with sprinkling water than is required for one marbling process.
For hair-veined edges, the sprinkling water is used in the same way as gall. Use a large painter"s brush or whisk and move the colors by beating into veins, with this brush or whisk through a slot, or throw the sprinkling-water upon the color by means of the sprinkling brush and sieve. In both cases the same result will be achieved.
ALUM WATER.
ALUM WATER.
In the chapter upon gall I have mentioned in a general way the action of alum water upon the edges, it remains only therefore to explain the preparation and application of the same.
To achieve beautiful results from the colors it is indispensable to wet the book edges or the paper, to be marbled, with concentrated alum water, so that no spot is left free from moisture, because at that spot the color would not take.
Concentrated alum water is prepared in the following way; put 2 quarts of water and 13 ounces of alum into a pot and heat until the alum is entirely dissolved. This concentrated solution is permitted to cool and is bottled tightly.
A solution of alum in cold water is much too weak for the above purpose as alum is but sparingly soluble in cold water.
The book edge or paper, which is to be marbled, is wet with a sponge dipped into this cold concentrated alum solution and must be allowed to dry for from 5 to 8 minutes, after which the produced edge may be lifted from the size. Generally this point finds but too little consideration in our book-binding establishments.
Edges which have not been treated with this alum water show as a consequence poor and blotted results, although such little trouble is necessary to wet the edges with alum water.