CHAPTER IV.
METHOD OF PAINTING FAIENCE UNDER THE GLAZE
WITH THE USE OF BODY COLOR.
The method of decorating pottery here described is similar in its effects to what is known as the Haviland, or Limoges faience, and is given as the result of numerous experiments made by the writer.
The finished work presents the appearance of a painting in oil, to which a brilliant glaze has been applied. This glaze not only renders the colors unchangeable, but gives a beauty and effectiveness which could be acquired in no other way. There is nothing peculiar in regard to this glaze, however, the only requisite being that it should be suited to the body of the ware, and that the latter and its glaze must not require so great a degree of heat in firing that the colors shall be injured. This matter of the glaze has been almost uniformly misrepresented in accounts of the ware which have been published. It has been said that the peculiar effect of the work was due to the glaze, and that the secret of making it was not generally known. This is not at all true, as the results are due solely to the peculiar method of painting, and the glaze is simply the process by which it is finished, and bears the same relation to it as the varnish does to the painting in oil. The work will suffer, of course, if this part of it is not well performed; but the distinguishing feature of the method consists not in the glaze, but in the use of clay, which is mixed with coloring oxides, capable of bearing a high degree of heat in firing, and which gives them body, producing a thick impasto in the painting. The work partakes, therefore, both of the nature of painting and modeling, as the high lights may be laid in so thickly as to produce an actual relief.
It is somewhat difficult, indeed, almost impossible, to give a correct idea of the palettes to be used in this kind of painting. If colors could be procured, already prepared for use, as oil paints are, and these colors had the same appearance after firing as before, it would be comparatively an easy task. As it is, the colors must be mixed with clays in certain proportions, and, on account of the change produced by firing, the proportions necessary to produce the intensity of color desired, can only be determined from experience. The result, after the work is finished, differs from its appearance before firing to a greater extent than in any other kind of decoration upon pottery. As a rule, it may be said that the colors are intensified by firing. This is also true of other kinds of under-glaze painting, but not in so great a degree as in the case in question. The harmonies and contrasts of color can be kept only in the mind of the artist, and every part of the work must be done with a view to the result when finished, which, as has been said, will differ materially from its appearance during the progress of the painting. Experience only, can give an accurate idea of these changes. This, however, is not an insurmountable difficulty; care and patience added to the requisite artistic ability, will soon lead to satisfactory results.
Before describing the method of painting, it may be well to consider the kind of clay of which the body of the ware should be made, and the state in which the painting should be applied. As to the clay forming the body of the ware, it must be of such a nature as to adapt itself to a glaze sufficiently soft to preserve the colors. As the clay used in the painting must, of necessity, in most cases, be white, in order that the purity and beauty of the colors may not be affected by admixture with it, a body of the same, or very nearly resembling it, would, in some respects, be the best, one reason for this being that the applied clay would be more certain to adhere firmly to the body, both having the same qualities. The proper glaze for such a body would, however, require too great a degree of heat in the firing, and none but the strongest colors could bear it without injury.
In order, therefore, that the glaze may be perfectly adapted to the body of the ware, and yet require no greater degree of heat than the colors used in the painting will bear, it is best to use a body formed from materials which do not need to be fired at a very high temperature. This desired quality is found in some of the natural colored clays. A mixture partaking of the qualities of both yellow and red clay, without the unpleasant color of the former, and possessing greater strength than the latter, has been found to be the best.
THE STATE OF THE WARE IN WHICH THE PAINTING SHOULD BE APPLIED.
For this method of decoration the ware should be in the “green” state. The more moisture it contains the better, and it will be in proper condition if procured as soon as it leaves the hands of the molder, or as soon as it has become sufficiently dry to retain its shape. Pieces can be kept in this state a considerable length of time, by placing them in a box which has been lined with plaster of paris. This lining should be about an inch thick, and if the inside is occasionally sprinkled with water, it will remain moist, and keep the clay in good condition. A box of this kind is really invaluable for all work, where it is necessary to keep clay moist. Within certain limits the clay is improved rather than injured by keeping in this way; the effect upon it being that it becomes tougher and more plastic. If kept too long, it becomes “rotten,” and the plastic quality is lost, but it will keep a reasonable length of time, even two or three months. If the box can not be had, the pieces may be covered by a rubber cloth, which should be kept from touching them by a frame of wood or galvanized iron wire, damp cloths having been placed around them to produce sufficient moisture.
It is necessary to exercise this care in keeping the ware moist, in order to prevent the clay, which is applied to the surface in painting, from cracking during the process of drying. It must always be borne in mind that the material made use of in painting is simply clay, which has been artificially colored, and, as clay, becomes subject to the rules which govern all work of this kind, whether it is making pottery, modeling, or painting faience.
To produce depth and richness of effect, the painting should have a heavy impasto, and the high lights should be laid on in such a manner as almost to present the appearance of modeling in relief. When this is done, there is a tendency in the applied clay to crack in drying, if the conditions are not right. In applying one piece of clay to another, it is requisite that both should be of the same consistency, to ensure equal contraction. In this case, however, the clay is used as paint, and must be of such consistency as will permit its manipulation with the brush. Its application, then, to a body of clay that has lost much of its moisture, is attended with some risk, and the fact that the coating of clay is comparatively thin, alone renders it possible to defy one of the conditions which govern the use of this material. When the piece of ware, upon which this painting is applied, has previously become too dry, the moisture in the coating of clay is very quickly absorbed into the body, and this causes it to shrink unequally with the body, and thus to crack. When the body and the applied clay are more nearly in the same condition, and the former still retains considerable moisture, it does not absorb that of the clay on the surface so rapidly, and they shrink and dry together.
The drying of the clay used in painting can, however, be retarded by the use of gum tragacanth, which may be mixed with it. It would, perhaps, be better always to take the precaution to use this medium, although when, as remarked before, the body of the ware is still quite soft, and the condition of the atmosphere such as to prevent too rapid drying, the painting may be executed simply with the use of water.
Just here a caution as to the use of gum tragacanth may be given, and that is, that it is better not to mix the gum with more of the colored clay prepared for painting than is to be used at once. When mixed only with water, the clay after becoming dry, can be easily rubbed down again with water; but if gum tragacanth has been used in the mixture, and it has been allowed to dry upon the palette, the gum will not re-dissolve readily under the action of water and the palette knife, and the mixture will be full of small particles of undissolved gum, which will render it unpleasant to work with. To prepare gum tragacanth for use, it is dissolved in water, to which may be added a drop of salicylic acid to keep it from turning sour.
The clay, which is to form a body for the colors, must be dissolved in water until of a proper consistency for painting. It should be a little thicker than the diluted clay used by potters and technically called “slip.” As to the quality of the clay, the desideratum is that it shall be colorless and not inclined to crack in drying. The clay used in the manufacture of white granite ware is probably the best clay for this purpose, generally accessible. This can be mixed with all the colors without injury to the tint of any. Parian clay produces the most beautiful effects, and, where it is possible to procure it, forms the best medium for this painting. More care must, however, be exercised in its use, as it is very liable to crack in drying, and from the translucency produced in the body by the action of the fire, must be laid on more thickly than clays which have greater opacity, to produce the effect desired.
In the case of yellow, which does not always stand the fire well, it is best to mix the color with a yellow-tinted clay to ensure a successful result. C. C. clay, which is a cream-tinted white, will effect this. If a darker yellow is desired, clay which in firing acquires a decided yellow-tint may be used.
A light cream-tinted clay, such as C. C., or “stilt” clay, may be used with yellows therefore, with advantage, with browns and blues without disagreeable effects; but in the case of scarlet, pink, or crimson and greens, nothing but white clay must be used, if purity of tint is desired. The reason for this is that the presence of iron in the yellow-tinted clays injures the colors mentioned.
The clay can be procured from the pottery in broken pieces, or, better, in a semi-pulverized state from the trimming in making the wares. When in this state it is easy at any time to dissolve enough for use. It is, perhaps, better to prepare it just before it is to be used, as the longer clay stands, after it has been mixed with water, the more compact it becomes. When it has just been dissolved, it still retains air among its particles, and this renders the mixture more porous and less liable to crack. It soon dissolves in water and can be stirred until smooth. It may be strained through a sponge, alternately allowing the sponge to absorb the diluted clay and then squeezing it. Probably the most convenient way is to rub the clay in a mortar until all the lumps are dissolved. If a very small quantity only is needed it may be rubbed down upon the palette with the palette knife as it is wanted.
A palette or a slab of glass may be used for mixing the colors and clay. The latter is the best, as it can be procured of large size, and as in this kind of work a considerable quantity of paint is necessary, there should be ample room to mix the colors. A slab of French plate glass, at least twenty by twenty-four inches, may be procured. This can be imbedded in plaster of paris, which will make it stronger, as well as furnish a white surface upon which the colors will show to better advantage.
The powdered colors as procured are not perfectly pulverized, and must be well rubbed down with a muller and palette knife. It is even more necessary in this than in other kinds of painting upon pottery that the color should be well ground. If not rubbed down sufficiently before being mixed with the clay, particles of color which are scarcely apparent before firing, will show when the work is glazed, forming specks in what should be, a perfectly uniform tint. If the color is mixed with the clay before it has been perfectly dissolved, it will not afterward be possible by any rubbing down to remove the specks from the mixture.
The colors, after being thoroughly ground, can be mixed with clay in such proportions as may be desired. The white clay takes the place of white, and is used to lighten every tint, as well as to form a body for the colors. It is a good plan, where experience has rendered it possible to do it with judgment and certainty of result, to mix the various tints in water with clay, in quantities, and then allow them to dry. When dry, they can be pulverized and the colored powder can be put away in bottles for future use. This saves time when painting, and also ensures a like result from the use of a mixture which has already been tested and found to be satisfactory. It is only, however, after considerable experience in mixing colors, and verifying their results, that this can be safely done.
As in other kinds of underglaze painting, it may be given as a general rule, that the colors are intensified in firing, in this, however, much more than in other methods. All the stronger colors are intensified to a degree difficult to realize before experience has taught the artist what to expect. They all become several shades darker, and, in the case of blues, blacks and greens, it is more difficult to obtain delicacy, than depth of tint.
In the use of scarlet, crimson and yellow, a considerable amount of the color in proportion to the clay must be used for the darker portions to give sufficient depth. Only enough clay must be taken to give body to the paint, and the mixture should then be applied very thickly. The painter must also bear in mind the fact that the stronger color will overpower the weaker in mixtures, even when the latter is in such degree as to give the color to the mixture before firing. After firing, the stronger color will appear in excess. In making such mixtures, therefore, the stronger color should be used very sparingly, if it is desired that the other should predominate in the tint when fired. Otherwise, the colors may be found after firing to be entirely different from what was intended.
METHOD OF PAINTING.
Let us suppose that the artist wishes to paint a vase. A certain tint being selected for the ground, the color, or colors, which are to produce it are mixed in their relative proportions, according to the hints given above. A sufficient quantity should be prepared to paint the whole ground, especially if a mixed tint, which it would be difficult to reproduce in its exact proportions. It will require some little experience to enable the artist to judge how much will be needed, and, perhaps, it will be somewhat difficult for any one accustomed to painting in other methods, to realize the quantity of paint used in this. It is better to have too much mixed than too little, as it can be kept and used another time.
The color, or colors, for the ground having been rubbed down until perfectly smooth, as directed before, may be mixed with more or less clay, according to the shade of color desired. The first tint may be made to represent the darkest shade in the ground, and a comparatively small amount of clay should be used. After the color has been mixed with the clay, it can be placed on one side of the palette. By taking portions from it and adding more clay, other shades of the same color may be made. First, a light tint may be prepared for the first coat upon the vase.
Before commencing to lay on the ground, it is well to wash the surface of the vase with a thin solution of glaze (such as is used for finishing the ware), or with borax water. This is to ensure the adhesion of the clay, of which the painting is to consist, to the clay of which the vase is made. Previous to this, the vase, if not already in good condition, should be washed over with a brush, or with a sponge dipped in water, or sprinkled until it has absorbed water enough to keep the clay, which is to be applied to its surface, from drying too quickly.
A broad, flat camel’s-hair brush may then be charged with the light tint, and the surface of the vase covered with it as evenly as possible, and so thickly as to completely obscure the body. This done, another tint, darker than the first, in a degree sufficient to permit their being distinguished from each other, may be mixed. This will form the middle tint of the ground, and is to be laid on over the first. The reason for applying two coats is, that, although it might be possible to paint one with the degree of thickness necessary to prevent the shrinkage of the applied clay in the firing, from revealing the body of the vase, still the beginner is very likely to be deceived as to the thickness of the impasto, judging by the eye alone. Potters dip pieces of ware in colored slips, and the thickness of the covering thus formed is all sufficient. In the case of painting, however, it is impossible to lay the clay on as evenly, and there will be, in all probability, some places too thinly covered to stand the fire, but which would not be revealed before. It is better, therefore, to apply two coats, so that one may cover up the deficiencies of the other. The reason for having these two coats of different tints is, that it is then possible to be assured that the surface is covered completely, it being easy to distinguish the first tint laid from the body of the vase, and in the second painting, to observe that it entirely covers the first.
The second coat finished, a lighter tint should be mixed, with which the ground is varied by touches here and there, making the highest light of the ground, while touches of the first tint mixed, give the darker shades. There should be difference enough in tone between the middle tints of the ground, and these lighter and darker tints, to produce a good effect of light and shade, and these touches should be laid on with a free hand, and then softened into the ground, care being taken that the lights and shadows should not end too abruptly.
In these touches, as in all the painting, there must be a certain thickness in reality, as well as in appearance, to make the work effective when finished. The clay shrinks and seems to be dissipated in the process of firing, and if applied too thinly, in any part, will reveal the body of the ware, or some under-tint, perhaps spoiling the appearance of the whole. The transparent effect, produced by a thin layer of clay, which, after firing, shows the under-tint through, is sometimes very beautiful in certain parts of a design. It is, however, difficult to judge by the eye of the requisite degree of thickness necessary to produce this effect, and the heat of the firing may be so great as to cause that portion of the painting to disappear entirely. It can not, then, be safely counted upon, and the best way is to depend solely upon the lights and shades of the painting for the effects desired.
The ground finished, the decorative design may be painted upon it. This should not be outlined upon the surface, but should simply be painted with a free hand, and without too much attention to detail, a brilliant effect of light, shade, and color being the object aimed at in this style of painting.
We will suppose that a floral design is to be painted upon the vase. The middle tint of the flowers can first be laid, the shadows are then put in, and lastly the high lights, laid on heavily, almost giving the effect of relief. Leaves and other accessories of the design may be treated in the same manner. The edge of the design must be softened into the background, to avoid a hard effect after the work is glazed. The process of glazing has a tendency to soften and melt the tints into each other, but this effect must be enhanced by judicious use of the middle tints and shadows of the painting, and by leaving the edges thin. One of the greatest beauties of this kind of painting, when well done, is the effect of the rich colors melting into each other, with a charming indistinctness, which leaves something to the imagination of the beholder.
Those who have not been accustomed to the use of color in such masses, will, perhaps, be embarrassed at first by the difficulty of painting with clay. This will soon be overcome by practice, but, as has been said before, it should always be remembered that it is clay which is used, and, therefore, the work is subject to the conditions which govern the use of that material.
It is unnecessary to enter further into details, as it is only intended here, to give some instruction as to the method of painting, leaving the manner of it to the artist, it being taken for granted that any one desiring to practice this kind of painting should have already attained some proficiency in the use of colors, and should have acquired a knowledge of the rules which govern art.
To such there will simply be the difficulty of learning to work with a new material. If this knowledge does not exist, it will be no easier to succeed in accomplishing any thing, worth the doing, in this, than in other kinds of art work.
With regard to the colors to be used, it is enough to say that a sufficient number can be obtained to produce by admixture, in various degrees, tints for the production of any subject required. It is only necessary to remember, as said before, that in these mixtures the stronger colors must not be in such proportion as to overpower the weaker. A list of useful colors has been given in a previous chapter. In regard to the mixtures of these colors a few words may be of use.
Black is a very useful color for shadows, making, in its admixture with white clay, numerous pleasing tints of grey, which may be varied by the addition of any other color which may be desired. As black is one of the strongest colors, however, it must be very sparingly used where a light tint is needed. In the mixture of blue and green, the former must exist in a much smaller proportion than the latter, if the mixture is to have a greenish tint. Experience alone can give success, but enough has been said to prevent the beginner from making very disastrous mistakes.
The painting must, of course, be executed while the clay is wet, and should be finished in one sitting. If this is not possible, it may be kept wet in the way described for keeping the ware before painting.
In describing the method of painting a vase, we have taken for our model, one decorated with flowers. Decorations can, however, be as varied in regard to subjects as paintings on canvas. Floral decorations seem to be the best adapted to vases, or other objects having rounded surfaces. Plaques and vases, such as pilgrim jars, which afford flat surfaces, may also be decorated with landscapes or figures. For these subjects somewhat different treatment may be adopted, but enough has been said to indicate the requirements of the material, and each artist will find a manner suited to himself.
Decorations of a similar character can be produced upon ware of different colors, leaving the color of the clay for a ground. This has a very good effect when done upon cream-tinted clay in suitable colors. As this kind of ware should be fired at a higher temperature than the deeper tinted and coarser clays, the colors are liable to fade in the firing. This is not undesirable, however, as the faded tints harmonize with the light ground much better than darker colors. Some beautiful effects can be produced by decoration of this kind, which can be supplemented by carving and gilding.
The same method can be used on a ground of dark red clay by the selection of colors which will harmonize with the ground. Yellow flowers look well upon a ground of this character, and the yellow color can be produced, as we have said before, by the use of yellow clay, either alone or as an adjunct to the color.
Monochrome decorations can also be produced, by the use of natural clays of various colors, in the same manner as that pursued in the use of the artificially tinted clay of which we have been treating. Good effects can be produced in this way, with the advantage that the colors will be fully retained in the firing. Red, or brown and white, in various degrees of combination, can be used to produce a design with every effect of light and shade. Also, red, with cream-tinted clay, or the three colors—red, yellow and white—can be used together. These designs can be produced upon grounds of cream, red, or yellow clay.
DRYING.
When the painting has been completed, it should dry very slowly, and it would be better, if possible, to effect this by placing it in a moist, cool place. It is, however, difficult to handle a piece of ware when wet. The clay is in a very soft state, and a sudden jar might cause the vase to fall to pieces.
If the vase has not been in proper condition for painting, or has dried too quickly, it will, after some hours have elapsed, begin to show fine cracks upon the surface of the painting. These may be stopped, before they have gone too far, by passing a modeling tool over them, or, if the crack has become too deep for this treatment, it may be filled with clay as nearly as possible in the state at which the body of the ware has arrived. If the cracks are allowed to go too far it will be difficult to stop them, as they may have extended into the body of the ware.
If the piece is permitted to go to the firing with any cracks, however small upon its surface, they will become widened in the firing, and, especially after the glazing, will show very distinctly.
In the biscuit, they may be stopped by filling them with powdered clay mixed with gum water. But an ounce of prevention is worth a pound of cure, and the safest method is to prevent their appearance in the first place. If this can not be done, they must be stopped as soon as they appear. The finer clays seem to have a greater tendency to crack in drying, and when the cracks have appeared, they are more difficult to stop than in other clays.
FIRING.
When the piece decorated is thoroughly dry, it should be fired at a temperature sufficient to make the body durable, and at the same time to perfectly fix the colors of the painting, so that there may be no danger that the glaze will cause them to run in the final firing. This latter defect may also result from an excess of glaze, and where it exists only in a very slight degree, produces a melting softness which is very pleasing. This effect is, however, so likely to be exaggerated to the ruin of the work that it is best not to run any risk of the kind in firing, and to depend upon the painting alone for the harmonious blending of the tints.
The temperature at which the work is to be fired, must, of course, depend upon the qualities of the clay of which the piece of ware is made. As has been said before, this clay should be one that does not require an excessive degree of heat in firing. The exact degree can be estimated by the potter who understands the requirements of the clay which has been used in the manufacture of the particular piece of ware in question. It may be said that the temperature at which Rockingham ware is fired is suitable for this work, and that a glaze such as that used upon that kind of ware can be used with good results. It is possible to have a glaze so adapted to the body of the ware as to prevent it from crazing, and yet preserve the brilliancy of the colors.