On the other hand, we have such a great painter as Josef Israels, who paid little or no attention to the materials which he used, with the result that many of his pictures are badly cracked and have darkened considerably in the shadows.
Once a painter is familiar with the colors which are permanent, he or she can proceed unconsciously without any technical interference and produce results which will stay.
There is a decided inclination at the present time towards impasto painting, in which colors are piled up to the thickness sometimes of a centimeter, and a plastic effect is sought by this means. This is a dangerous proceeding, excepting in the hands of one who has a distinct knowledge of how colors dry. Lamp Black and Graphite, for instance, will take many years to dry thoroughly hard. Zinc White, Raw Umber, Burnt Umber, Sienna, Indian Red and Red Lead or Orange Mineral will dry hard and brittle, with the ultimate danger of falling off the canvass. Then again, the pigments I have just mentioned, like Lamp Black, and which take years to harden, will crack any hard drying pigment which is placed over them, because in drying, the slow drying colors wrinkle and contract, and a hard drying color placed over them, not having sufficient elasticity will be torn asunder, and a small crack, which may widen into a fissure, will take place. The whole idea of permanent painting, then, simmers itself down to one of sense and judgment. No one has ever seen a Water Color painting which is cracked. This is due entirely to the fact that the pigment is so thin that it cannot crack. Linseed Oil, when exposed to the air for several years, changes into what is known as fat oil. This is a thick, ropey, pale material of the consistency of honey, and when used too freely dries with a film similar to that of a withered apple. Placed in a warm place, instead of baking, it shrivels up and wrinkles.
Blakelock and Ryder poured thick coats of varnish over their pictures when the paint was insufficiently dry, with the result that many of their paintings to-day show cracks and fissures, due to this practice. Blakelock used a very heavy-bodied Linseed Oil, which was so viscous that it flowed down in many places and formed “curtains,” and teardrops.
Blakelock painted with fat oil, and many of his pictures show this wrinkling effect, and as no varnish is added to fat oil, the chances are it will remain absolutely permanent, if used thinly or sparingly.
MADDER LAKE AND HARRISON RED
BOTH of these colors are aniline colors and therefore artificial. There is some Madder Lake on the market which is made from the Madder Root but it does not differ from the artificial in the slightest degree and both the natural and the artificial are absolutely permanent under normal conditions. The artificial is sometimes sold under the name alizarine.
Madder Lake is transparent when used as a glaze and it can be mixed with a number of pigments with which it does not interact, but it must not be mixed with the iron pigments that contain water, and these are principally all the Ochres and Siennas, but as a glaze it may go over any color without being decomposed. It has a record for permanency of several hundred years and is at least of essential importance in portrait painting.
Harrison Red is rather a complex aniline color, exceedingly brilliant, but it has some defects which the painter should know. In the first place it bleeds very slightly, that is to say, if Zinc White or Flake White is painted over pure Harrison Red, the Zinc or Flake will turn a pinkish brown, which is due to the fact that the linseed oil, or other drying oil will absorb part of the dye out of Harrison Red. The painter, therefore, in using Harrison Red must be careful of this defect. Harrison Red must not be mixed with an iron color like Ochre, Sienna, or Raw Umber, otherwise its brilliancy is slightly marred. It is similar in many respects to Deep Vermilion, excepting that it is many times stronger than Vermilion. It can be reduced with Permanent White (Blanc Fixe) without materially lessening its brilliancy.