Rembrandt created his distinctive portraits with a small palette of colors dominated by dark earth tones and golden highlights. He was a master of chiaroscuro, an Italian term for a style using strong lights and heavy shadows to create depth in a painting and a center of interest. Rembrandt used it to emphasize the faces and hands in his portraits; what his subjects were wearing and their setting are of less importance, melding into a dark background.
A modern version of Rembrandt’s palette should include yellow ocher, burnt sienna, burnt umber, white, black, and a brownish or orangey red such as cadmium red deep. ‘Break’ the colors by mixing them -- Rembrandt was known for his complex mixtures rather than raw color (our equivalent of ‘straight’ from the tube). To get a bluish gray, he’d mix ground charcoal into white paint. Rembrandt worked on a colored ground, never white. He used mostly a gray or grayish brown; these got darker as he got older.
Rembrandt may have been restrained in his choice of colors, but there was nothing restrained about the impasto way he applied them, particularly later in his career. The Dutch artist and biographer Arnold Houbraken commented that the colors in a portrait of Rembrandt’s were “so heavily loaded that you could lift it from the floor by its nose.” Rembrandt developed his paintings on the canvas, moving around paint even when it was very thick. The effect you’re after is called sprezzatura, or “apparent carelessness”. How deceptively simple Rembrandt makes it look!
See Also: Night Watch Painting by Rembrandt