Cone 6 oxidation: Black Matte is formulated to produce a smooth matte surface. Light coats will allow clay body characteristics to appear through the glaze (especially on dark and speckled clay bodies).
Cone 10 reduction (second image): Color darkens.
TIP: A true matte finish at cone 5/6 with no movement. Thicker application, three or more coats, will produce a more opaque finish.