In some woods, and some finishes, the observer seems to be able to look down into the wood. When the angle of incidence (to the light) and the viewing angle (relative to the wood surface) change, the wood seems to change colour. Figured walnut, crotch mahogany, satinwood, birdseye maple, all show depth. Basswood, pine, oak (exceptions include quartersawn white oak) do not show depth. Dye stains enhance that appearance while pigmented stains lessen it.
The real or simulated distance from the point of an image that seems closest to the viewer to the point that seems farthest from the viewer. Simulated depth may be created by perspective, overlapping, size, tone values, colours, and so on.
That colour quality, an increase in which is associated with an increase in the quantity of colorant present, all other conditions (viewing, etc.) remaining the same.