Ultramarine and Mars Black are mixed with a hint of Crimson to create a gray that makes an excellent substitute for black.
You can use Payne's Gray for painting anything you would normally see as black. The night sky, an animal's fur, a suit and top hat on an upstanding gentleman... The only limit is your imagination. You can even prepare a scene with minimal light and use this gray as a stand-in for warm colors.
True blacks are difficult to find in nature. What we see as black can often be better served by a gray like Payne's. The ultramarine and crimson give the gray warm undertones without making the color too light. When painting in grayscale, monochrome, or full color, this gray is an essential part of your palette.