I like to print on stationery with a pre-printed letterhead using the Preview.app and a duplex-capable HP PostScript (Color Laserjet 4700) printer. One would think that pre-printed stationery could be placed into one of the trays and then printed on front and reverse side. Unfortunately, the print dialog handles one and two-paged documents differently: the stationery needs to be placed differently into the tray if the document contains one page versus when it contains two pages. This is not obvious when printing on plain paper but becomes obvious once you mark, say, the upper left front corner of pages and then print different documents on them.

I checked the PostScript code generated and indeed it is different for one versus two-page documents with respect to duplex printing, probably causing the difference in paper handling. Obviously this makes it difficult to print pre-printed stationery in duplex mode.

I expected others to have stumbled upon this but could not find specific help so far. Any ideas? This is on OS X 10.6 and I checked two different printers.