There are further types of Tempera Colors on the market which contain little or no albuminous material, but which are simply mixtures of linseed oil and water. I am refraining from discussing scientifically the manufacture of emulsion paints, because that has been described fully and at great length in another publication.[4] So that, for the present, it is only necessary to say that it is a simple matter to combine oil and water for Tempera painting. There are paints on the market sold under the name of Matte Colors and Tempera Colors, which are emulsions of linseed oil and water only. But, these have neither the plasticity nor the smoothness of film, after they are dry, of the Tempera Colors which contain albumen. If the artistic painter will use only those pigments previously described which are permanent, whether they be ground in Linseed Oil or whether they be Tempera Colors, and a medium so prepared that noxious gases cannot penetrate through either side, absolutely permanent results will be obtained.

WATER COLORS

WATER Colors are either put up in little cakes, in pans or in tubes. In every instance, they are ground very finely in a watery Medium to which some glutinant material has been added, such as Gum Arabic; and, in the case of tube colors and pan colors, Glycerine, sugar or Glucose, to prevent them from hardening or drying out entirely. Water Colors, excepting those of the Tempera type, which contain oil, cannot be varnished, but they are “fixed” with a solution of gum or Casein, so that they do not rub off or drop off of their own weight. There are entirely too many unstable Water Colors made. Some manufacturers carry as many as one hundred and forty different pigments in cakes, pans and tubes.

A generation ago some artists fixed their water colors by means of Gum Arabic. In some cases the gum shriveled up and became opaque. Water colors should, of course, never be varnished, but may be fixed, if necessary with a very weak casein solution.

The perfect and simple palette of Water Colors is practically the same as that of Oil Colors, with a few additions, as follows:

A Water Color painting must be hermetically sealed in the frame and it must not be backed up with a thin Veneer of wood, for time and again these wood veneers contain knots which are very resinous, and these resins, in a warm room, will evaporate, strike through and form a yellow spot or ring on the painting itself. The best way to frame or hermetically seal a water Color, in order to make it permanent, is to have a glass front and the glass should be fastened around the inner edge of the frame by means of a strip of adhesive paper to exclude air and moisture. The Water Color is then inserted and backed up with a piece of cardboard, academy-board or thin metal, such as Zinc, Aluminum, or even Sheet Iron. When this has been thoroughly fastened by means of brads or nails, the entire back of the picture is then sealed with heavy paper which has been thoroughly soaked on both sides with a good glue or starch size. In this manner a Water Color will remain permanent. A strip of wood, a quarter of an inch thick, should be inserted between glass and drawing, so as to prevent the paper from resting against the glass. Water Color pigments may be mixed with each other without danger of reaction, because, once they are dry, no further reaction will take place, as dry colors do not interact. An exception, of course, must be made in the case of Flake White and Ultramarine Blue, although Flake White as a Water Color is totally unnecessary. The question of the hiding power of Flake White as compared with other colors, will be mentioned later. But, a good coating of fixative, whether it be composed of a glue size or a Casein size, or even an alcohol varnish, is essential in the protection of Water Colors from atmospheric effects.

Colors Which Are Absolutely Permanent Which Are Not Generally Used And Which May Be Mixed With Any Other Color Without Decomposition—Not Mentioned in the Simple Palette.

Colors Which May Be Used Alone And Which Are Perfectly Permanent After They Are Varnished.