I just purchase a Speed Graphic 4x5 and will arrive sometime next week. Smart ass that I am, I decided to purchase a Polaroid back for it without doing much research, ( I believe the good one is the Polaroid 545 film holder) hey I am honest, saw it for sale locally and purchased and picked up the same day. To late now, here is the link to see item: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=280303152883 I believe I could put Polaroid film type 55 into this vintage land back heavy thing, the question is, would it go at the back of my Graflex Speed Graphic? That's where I started to be concerned about it...until camera arrives I won't be able to have a clue, you know, I am also new to 4x5 anyway. As someone told me once in a street market, if it doesn't work? you can always put it up for decoration in a shelve? Thanks in advance, Jaime.