no feathering

with feathering
The feather commands adds a soft edge to a selection. The amount of feathering is configurable, from a small to large.

This technique is almost required when using selection masks for photo editing, without feathering hard edges will be clearly visable.

Step-By-Step: Feather

1. open sample image

2. create a selection mask

3. open feather command

4. set a feather radius of 30 pixels

5. invert the selection

6. apply changes, for example reduce the brightness to darken the selection. notice that the edges blend smoothly

7. experiment with different feather values

no feathering
  30 pixel feathering
  60 pixel feathering
Practical Tips:

feathering is an important part of using selection masks. You should experiment with differant feather values as each situation may require slightly different settings.