Hasta La Motion!

Hello, I would like to view the image I am working on brighter so that I can see it more clearly. I know that I could just create an adjustment layer, put in on top of everything and increase the levels, this works but then when I paint on it, everytime I sample a color from the image it picks from the bright verison of it so the color I want is obviously brighter than the original, the same applies to the clone brush. In silouhette there is a way of changing just the way you see the image without actually affecting it, so I was wondering if there is something similar in photoshop too or if there is any way I can do this. Thanks!