I had a similar workflow question in regard to Topaz Studio and this thread is specifically what I was wondering. I'd love to test this but still waiting for the Topaz Studio Photoshop Utility batch file to be fixed so I can install it as a menu item in Photoshop CS6.
I've had the stand alone version of Impression 2 for awhile and was a little disappointed that it wouldn't open PSD files, but I'm assuming now that its not recognizing layered file formats is by design. Not a big deal really. My normal workflow is to duplicate a layer before applying any of the effects so hoping the Studio route will allow me to stay in Photoshop & simply send the one layer to it.
So in order to run some quick tests, I flattened & saved off to a TIF. In doing so however, I discovered something and am no wondering if it's related.
Saving off as a TIF in Photoshop will retain Alpha channel(s) unless you specifically remember to uncheck that option in Pshop's first dialog box. The second dialog is for TIFF compression and even though the Save Transparency option is unchecked (yet grayed out), the alpha is retained no matter what if you forgot that in the first step.
So, since I work with Alphas channels A LOT, that leads to to make a
*** FEATURE REQUEST ***
Topaz Studio needs the option to disable or delete a file's alpha if present. If I open a file with an alpha, the transparency gets applied and there's no way to have it not do that. Yet, in the Preset panel it's displayed w/o it. See attached.