Sprite Shading

Hi, how can I make my 2d sprite character look darker when he enters a cave or dark room? I want to keep all the colors but make them darker. Is that possible?

I have no light source, just the original colors of the png files which made the sprite



You can set the color variable on the sprite renderer to grey when you enter a dark place then set it back to white when you are in a light place.

The closer the color is to black the darker the sprite will become.