I recently had to deal with both(WIA and TWAIN), and I do think that the fact that twain says what is mandatory for a driver to be compliant is a lot better than WIA that does not says about anything to be mandatory.It just so happend that in twain I could use an HP scanner and in WIA I could not, simply because WIA does not care to make mandatory something a lot more critical than color depth and resolution: the page format. Simply put, I could not set programatically the format of the page to be scanned, and as a result the european A4 format was simply chopped to the american “letter”, wich rendered my software and one month’s work useless.:evil:
Oh, and another thing: TWAIN is actually a consortium of important scanner producers who obviously do not wish their scanners to become NOT TWAIN compatible, or to have to spend a few millions on updating their scanner drivers with zero profit, so it is a miracle that twain even has mandatory functionality that must be implemented. So TWAIN Is better than WIA. One more funny thing about WIA: the Interface lets you belive that ADF scanning is by default both-sided. Single sided ADF is designed as an “Avanced Feature”. 🙁