coloration vs colouring

coloration and colouring both are nouns.

Word	Noun	Adjective	Verb	Adverb
coloration	Yes	No	No	No
colouring	Yes	No	No	No

As nouns, colouring is a hypernym of coloration; that is, colouring is a word with a broader meaning than coloration:

coloration: appearance with regard to color
colouring: a visual attribute of things that results from the light they emit or transmit or reflect

Other hypernyms of coloration include color, coloring, colour.

coloration (noun)	colouring (noun)
choice and use of colors (as by an artist)	the act or process of changing the color of something
appearance with regard to color	a visual attribute of things that results from the light they emit or transmit or reflect
the timbre of a musical sound	a digestible substance used to give color to food