Hello!

I have a quick question regarding a painting idea I had for our first nursery.

I'm doing a nature theme, with a grass green lower band and a sky blue upper band both going all around the room. I wanted to have one wall darker so that it looks more like night time. Is it possible to do a wash over the previously painted colour bands so that it still looks like the same scene, just at night?

Also, is there a colour you would recommend for this?

Thanks!!