According to my experiences, you can find very useful information regarding the supported capabilities at this web pages:
http://www.dosadi.com/vendors.htm
http://www.dosadi.com/twister-reports.php
Our Morena Image Acquisition Framework for Java contains TwainAutomatedTest program (test.bat) in the examples directory of the distribution package. It will write all supported capabilities of your scanner to the twainAutomatedTest.txt file.
If your scanner supports hiding it’s user Interface, you can also run our online MorenaCapabilities example:
http://www.gnome.eu/Twain/examples/capabilities.html
1) First select your Twain or Sane source.
2) Click to the “Custom dialog window”/”Select capabilities”. The dialog window will pop up all supported capabilities/options.
Martin Motovsky
Member of Gnome’s technical support