The colouring of something is the colour or colours that it is.
Other countries vary the colouring of their bank notes as well as their size.
其他各国钞票的色彩和大小各异。
Someone's colouring is the colour of their hair, skin, and eyes.
None of them had their father's dark colouring.
他们无一人具有父亲的深肤色。
Colouring is the act of using dyes or paint to change the colour of something.
They could not afford to spoil those maps by careless colouring.
他们不敢用随意的涂色毁了那些地图。
Colouring is a substance that is used to give colour to food.
A few drops of green food colouring were added.
几滴绿色的食品色素被加进去了。