This simple recipe will show you how to change a layer mode to the Overlay mode:
In the Layer palette, click on the layer to edit (if the Layer palette is not visible, navigate to Window | Layer to open it).
From the top-left corner of the Layer palette, click on the drop-down menu. Then, click on the Overlay mode.
This mode combines colors by applying either Screen or Multiply, depending on the overlapped colors. Bright areas become brighter, while dark areas become darker. In the preceding example, the central rectangle has disappeared from the region where it overlaps the white background, but it has become light yellow and golden yellow across the top stripe, and light purple and bright purple across the bottom stripe. The blue vertical stripe has all but disappeared across the top yellow stripe, and has become a medium blue in the area where it overlaps the purple one. The vertical red stripe has become golden yellow across the top stripe...
