light turns dark..

I painted last night. Had a good idea on a piece. It was coming along, but then It came to a point where I realized I needed more umph to the piece. So I mixed a few colors and then it got dark. It was a nice bright yellow, blue and orange mix of paint but then I mixed a bit too much dark blue and brown where the piece got a bit too dark for my liking. All my pieces somehow come out a bit too dark. I think I'm going to add a bit more white to it after the first coat dries. Hopefully that will brighten things up.