Verdaccio is an Italian name for the mixture of mars black and yellow ochre resulting in a grayish or yellowish (depending on the proportion) soft green.

Verdaccio became integral part of fresco painting where this color is used for defining tonal values, creating complete monochromatic underpainting. Often architectural details in frescoes are left in Verdacchio without any additional color layers, best example is the ceiling of the Sistine Chapel, where you can clearly see verdaccio underpainting left as is on all architectural details of the composition.

The technique of underpainting in verdaccio became known as Verdaccio.

In oil painting a similar technique is used by flemish painters which is referred to as the "Dead Layer". "Dead Layer" is applied over the traditional burnt umber underpainting to refine the values and remove the warm tone of umber. The resulted "white to olive green to black" underpainting is like "like being lit by a moon light" which does not affect the tonality of the final painting.