I have been reading Amy Butler Greenfield’s A Perfect Red, and it has already sent me off in several directions.

That is usually how I know a book is working on me. It does not stay inside its own covers. It starts attaching itself to other things I am looking at, writing about, or painting. From this one book, I found my way to Rembrandt, to cochineal, to Cornelis Drebbel, to military uniforms, to trade routes, to insects, to empire, to the astonishing fact that a color can carry half the world inside it.

That is the great subject of A Perfect Red: not red as an idea, or red as a symbol, but red as a material fact. A color made from tiny insects. A color people desired, guarded, stole, traded, imitated, taxed, wore, painted with, and fought over.

A color is never just a color.

While reading Amy Butler Greenfield’s A Perfect Red, I came across Titian’s portrait of Charles V on horseback.

The moment I saw it, I thought of Rembrandt’s The Polish Rider.

That surprised me. I do not know Rembrandt’s work particularly well, and I had never seen the two paintings discussed together. But the connection was immediate. Not scholarly. Not proven. Just visual.

There they were: two riders, two horses, two paintings separated by roughly a century, and something in the structure of one seemed to call out to the other.

Did Rembrandt know Titian’s painting?