
Opacity
Opacity: O
This colour is considered “opaque” meaning that the coverage is full, layers underneath are not visible.
Opacity: SO
This colour is considered “ semi opaque” meaning that the coverage is not entirely full, layers underneath are semi visible.
Opacity: T
This colour is considered “transparent” meaning that the coverage is not full, layers underneath are visible.

Lightfastness
Carbon Black: ****
Four stars indicates that this colour is on the highest end of lightfastness scale; four stars is the maximum.
A pigment is considered to be lightfast, or light stable, if it resists fading over extended exposure to ultraviolet light. A pigment that cannot stand up to direct exposure to UV rays without fading is considered to be fugitive.