Although historians tend to see Rembrandt’s method as an attempt at naturalism, it goes much farther than portrait conventions have ever gone, then or since. Consider what is happening in the paint, aside from the fact that it is supposed to be skin. Paint is a viscous substance, already kin to sweat and fat, and here it represents itself: skin as paint or paint as skin, either way. It’s a self-portrait of the painter, but it is also a self-portrait of paint. The oils are out in force, like the uliginous oozing waters of a swamp bottom. The paint is oily, greasy, and waxy all at once—even though modern chemistry would say that it is impossible. It sticks: it is tacky and viscid like flypaper. It has the pull and suction of pine sap. Over the far cheek, it spreads like the mucilage schoolchildren use to glue paper, resisting and rolling back. On the nose—it’s rude, but appropriate—the paint is semi-solid, as if the nose were smeared with phlegm or mucus. On the forehead, it looks curdled, like gelatin that is broken up with a spoon as it is about to set. There is drier paint around the eyes, and the bags under the eyes are inspissated hunks of paint, troweled over thin, greyish underpainting. The grey, which is left naked at the corner of the eye and in the folds between the bags, is the imprimatura, and the skin over it is heavy, thick, and clammy. The same technique served for the wings of the nose, where dribbles of paint come down to meet the nostril but stop short, leaving a gap where the grey shows through. Of course, the nostril is not a hole, but a plug of Burnt Sienna with Lamp Black, and it also lies on top of the grey imprimatura. Rembrandt’s thin moustache is painted with wiggles of buttery paint, almost like milk clinging to a real moustache. Over the eyes and eyelids there are thick strips of burned earth pigments—Lamp Black and Burnt Sienna—covering everything underneath. The tar spreads up and inward, and then falls into the hollows between the eyes and the nose in dense pools like duplicate pupils.
There is no limit to this kind of description, because Rembrandt’s paint covers the full range of organic substances. It is more fully paint, more completely an inventory of what can happen between water and stone, than the other examples in this book. And that means it is also more directly expressive of qualities and properties: it is warm, greasy, oily, waxy, earthy, watery, inspissate. It is not dried rock, like Monet’s cathedral, nor water, like his marine paintings. The thoughts that crowd in on me when I look at this paint have very little to do with the underlying triad, or with the named pigments or oils. They are thoughts about qualities: I feel viscid. My body is snared in the glues and emulsions, and I feel the pull of them on my thoughts. I want to wash my face.
This is how substances occupy the mind: they congeal it into their own image. The painter’s face comes a portrait of the substances that filled his mind.
For the alchemists all this was usually terribly literal. They often wanted to eat what they had made, as if the ingestion would transport the qualities into their bodies where meditation would not. Edible gold was a common goal. Some recipes are genuinely edible, even if they wouldn’t be good for you (there are mixtures of gold and honey, and gold and salt). Others are poisonous. Joseph Du Chesne, a late sixteenth century physician and alchemist, tells how to make edible gold by pouring blue vitriol (copper sulfate pentahydrate) over tin powder, resulting in “the most beautiful yellow water in the world.” It is left overnight, and then the next day the alchemist pours it over gold leaves and adds “very fine brandy” (tres-excellente eau de vie). If it is heated long enough, the gold will turn to oil, and can be taken internally for “all diseases of the lungs, the stomach, and the heart, in short, for all kinds of illnesses and infirmities ... It is also excellent for the prolongation of life and the prevention of all kinds of diseases.” This is the quackery that eventually hurt the alchemists, but it also has its deeper truths. There is something beneficial about seeing gold turn into yellow water, and then to oil, just as there is something eloquent and unanswerable about Rembrandt’s pastes. It could even be said this way: substances not only occupy the mind, they become the mind.