Is it possible to create clipping paths from masks created in Mask Pro?
If you used Mask Pro Select you are returned to Photoshop with a selection. Then go to Select->onOne->Mask Pro Make Work Path and try the default settings, this will create a path. Then go to the Path’s palette, select it and make it a clipping path.
If you used Mask Pro you are returned with no selection, but your subject will be on a transparent layer. Use the magic wand tool to click in the transparent area, which will select only the transparency, then invert the selection. Now you have a selection of just what you want, then go to Select->onOne->Mask Pro Make Work Path and try the default settings, this will create a path. Then go to the Path’s palette, select it and make it a clipping path.
There are some caveats to using clipping paths. They are a rather old technology that doesn’t understand transparency, it is just like cutting something out with a knife. This can yield hard edge transitions, what you would call helmet hair on people. Considering all modern page layout applications support native transparency in Photoshop files (InDesign CS2, CS3 XPress 6.5 and higher) which will give much better results if you just use Mask Pro to paint away to transparency. The only use for clipping paths today is if you wanted text to wrap to a curve, which can still easily accomplished by creating a hidden curve in the layout application, which is the better way to do it because you have more control and it is editable.

