Next, you will refine the selection of the egret by adding to or erasing parts of the masked area. You’ll use the brush tool to make changes to your quick mask. The advantage of editing your selection as a mask is that you can use almost any tool or filter to modify the mask. (You can even use selection tools.) In Quick Mask mode, you do all of your editing in the image window.
In Quick Mask mode, Photoshop automatically defaults to Grayscale mode. The foreground color defaults to black, and the background color defaults to white. When using a painting or editing tool in Quick Mask mode, keep these principles in mind:
Painting with white erases the mask (the red overlay) and increases the selected area.
Painting with black ...