Am at a loss. Have a new image which is the scan of some music. Using Magic Wand, I selected all music from paper background and created a Channel selection. On a new layer, Music layer, I did a black fill of the selected music. I then place a white layer below below it. The selection of the original music carried with it blemishes: small black marks, and a few very light gray areas. When I select a blemished area, the selections under Edit are all gray ... not active. Nor can I use the Brush tool to paint on the layer. What am I doing wrong?