Overlap Inverted Layers Seamlessly

Overlap Inverted Layers Seamlessly

Suppose you want to slice a layer into segments and adjust
each segment individually but let them appear combined
in the fi nal result. A gap will appear along the threshold
areas of the matte for the reasons explained in the Opacity
section earlier; two overlapping 50% opaque pixels do not
make a 100% opaque combined pixel.

Just as the name implies, the Alpha Add blending mode
directly adds transparent pixels, instead of scaling them
proportionally (Figure 3.23). You can cut out a piece of a
layer, feather the matte, apply the inverted feathered matte
to the rest of the layer, and recombine them with Alpha
Add applied to the top layer. The seam disappears.