It appears there was a formulation change to Van Dyke Brown. It was previously PBk9 PBr7 (Burnt Sienna and PBk9 Ivory Black). The previous description read, "Van Dyke Brown is the warmest Gamblin black, a good glazing color and useful for adding "gallery tone". Completely lightfast and permanent, this oil paint is made from bone black and iron oxide.“ -Gamblin Oils. It now contains Ultramarine. Gamblin classifies this as a black paint that leans to the warm side. More information and a comparison of colors can be found at https://gamblincolors.com/choosingblackoilpaint/