Threshold Worksheet
I. Creating Selections Using Threshold
A. Threshold Adjustment Layer
1) Create a Threshold Adjustment Layer from in the Layers palette.
2) Adjust the Threshold Level until the appropriate separation occurs between the subject and its background. Click OK.
* This method works great to replicate natural edges such as foliage.
3) Grab the Magic Wand and click on the area most easily selected in either white or black. Be sure that both colors are definitively separated.
* The Magic Wand easily selects due to the reduction in number of colors.
4) With the selection still active, Trash the Threshold Layer to regain normal view of your image.
* This method can only be completed with the use of Adjustment Layers.
5) Double-click the Background Layer and Name accordingly.
* The Background changes from Locked to a New Layer that can be altered.
6) With the selection still active, go to Select>Menu>Inverse Selection.
7) Add a Layer Mask by clicking on the Layers palette.
* White reveals and black conceals info on Layer Masks and Alpha Channels.
8) It is now possible to add a new background such as a sky to the image.
9) Use a Gaussian Blur on the Layer Mask of the image to feather edges.
* This will soften and smooth the edges to enhance transition.
10) Lastly, if halos around your selection edges are detected, go to
Select>Modify>Contract and reduce the selection edges by a few pixels.
*Repeat these last few steps as needed for final enhancement of imagery.
© 2007, Matthew Roderick |