The precision of the canvas: 8-bit samples on an 8-bit color canvas, 16-bit samples otherwise, as a layer has. This is the default.
EightBit
1
8-bit samples (Rgba32) on every canvas: the tile is drawn as on an 8-bit color canvas, then painted as an image of 8-bit samples is, as browsers rasterize the drawing of a canvas (a CSS paint worklet) into an 8-bit bitmap.