Michael E. Stern
Build A Better Photograph dot com
Calculations Masking Technique Checklist:
Peruse each Channel to identify the Channel with the most contrast along the
border of what you want to keep and what you want to mask out.
Go to Image > Calculations. Make sure the right document has been targeted
first. Choose the aforementioned Channel twice and using a Blend Mode,
attempt to get the a high contrast edge:
After hitting OK, go to the Channel. Now called Alpha 1.
Go to Levels (command L), set the Paint Mode to Overlay and using black and
white paint along the edges with a 50% opacity (or less), soft brush:
Paint with black to darken edges. Paint with white to lighten edges. Be careful
not to go too far as this will result in an unacceptable edge.
To paint inside the selected area change the Paint Mode to Normal. Use black.
The finished mask should be 100% white and 100% black. No gray allowed.
Refine Edge Masking Technique Checklist:
Use the Quick Selection Tool to paint in a selection edge. Hold down the Option
key to subtract from the edge.
Use Quick Mask Mode (Q) to help visualize the masked area. Go in and out of
this mode as needed.
In Quick Mask Mode, paint with black to add to the red mask and paint with
white to erase.
Refine Edge Dialog Box:
Paint along the selection edge to help Photoshop understand calculate what to
mask and what to leave alone. This is especially good for subtle things like hair
and soft edges. The Option key subtracts from the edge. Sound familiar?
Adjust Smoothness, Feathering, Contrast and Shift Edge while looking at your
Use Output at about 50% to help blend edges around the softer edges. This
does depend on what you are putting the object into.