concrete rules and abstract machines

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Not long afterward, he began building up the opaque passages in his lights more heavily, and texturing them to take on the physical convolutions of the lighted surfaces of his subjects, most notably the skin textures of male subjects, including himself. The texture was created, or at any rate can be duplicated, by applying the paint somewhat heavily with large brushes, then gently passing a large, dry, soft-hair brush over the surface of the wet paint, back and forth, until the desired texture is attained.

The consistency of the paint was modified by the addition of a medium containing a long oil (sun-thickened linseed or walnut oil or boiled oil) and sometimes a resin, to give it a long brushing quality. Paint exposed to the air for several hours begins to take on this same characteristic, as the oil begins to polymerize.

Subsequently Rembrandt began to superimpose glazes of red over these textured passages when dry, then wipe them off with a rag, leaving traces remaining in the low spots to create an even more convincing texture of rough flesh. Someone, at some point, said you could pick up a Rembrandt portrait by the nose.

As he began to expand the effect of glazing over dried impasto to other textures as well, he devised a method employing two whites; one for impasto and one for smoother passages. The impasto white was faster-drying, probably made so by the addition of egg, and possibly chalk, into the formulation. In any case, it was very lean, and consisted mostly of white lead with a minimum of binder. He began applying it more and more heavily as the first stage of a two (or more) stage operation which was finished with transparent glazes and wiping to create fantastic special effects.

The most extreme example of this is the man’s glowing, golden sleeve in the painting referred to as “The Jewish Bride,” in the Rijks museum in Amsterdam. The brilliance of this effect cannot be obtained in any other way. He has used the same technique on the bride’s costume in the same painting, but here the underpainting contains vermillion, and is glazed with red lakes, perhaps Rose Madder. The gold chain in “Aristotle Contemplating the Bust of Homer” is done in much the same way. The underpaint appears to have been troweled on with a knife or some sort of flat stick, then sculpted before it dried.

In the Lieutenant’s uniform in “The Night Watch,” Rembrandt used this method, but with less heavy impasto, for the ornate brocade work. The wet underlayer, which in this case included Lead-Tin Yellow, was worked with sharpened brush handles and other tools while soft, then allowed to dry before the darker glazes were applied. By wiping the glazes off while they were still wet, Rembrandt was able to create a bas-relief effect of remarkable three-dimensionality as the glaze remained in the nooks and crannies. By glazing again, this time with transparent yellows and/or browns, instead of Ivory Black, he gave the textures a rich, golden glow.

He is known to have sometimes used Asphaltum as a glaze, for the most part successfully overcoming its tendency to crack and wrinkle by keeping its percentage low in a mixture with Sandarac varnish. The reader should note that both Asphaltum and Sandarac are problematic substances, risky to use in painting, and are unnecessary now that synthetic substitutes for both have been developed, which do not share the defects of the older materials.

A full range of transparent browns may be mixed from Transparent Oxide Red and Phthalocyanine Blue, the relative warmth or coolness adjusted by varying the proportions of the two, while the Sandarac is best replaced by an alkyd painting medium.

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