What is the colour of dark

Colour of dark is not black. Yes you have readed that right

Many of as accept what our eye shows as but due to that the reality doesn't change.
Our eye can shows as what it can see.

We can define darkness as area with no light. Not as colourless area or Black area

In terms of physics, an object is said to be dark when it absorbsphotons, causing it to appear dim compared to other objects. For example, matte black paint does not reflect much visible light and appears dark, whereas white paint reflects lots of light and appears bright. An object may appear dark, but it may be bright at a frequency that humans cannot perceive.A dark area has limited light sources, making things hard to see. Exposure to alternating light and darkness (night and day) has caused several evolutionary adaptations to darkness. When avertebrate, like a human, enters a dark area, itspupilsdilate, allowing more light to enter the eye and improvingnight vision. Also, the light detecting cells in the human eye (rods and cones) will regenerate more unbleached rhodops in when adapting to darkness.

One scientific measure of darkness is the Bortle Dark-Sky Scale, which indicates the night sky's and stars' brightness at a particular location, and the observability of celestial objects at that location

So remember dark is lightless not colourless or Black.