need some aperture/z3100 veteran advice

having wasted many feet of a 24 " roll of Hahnemuhle photo rag 310# trying to print from Aperture to my z3100 - HOW DOES APERTURE 2 handle margins?? i like to print a 2 " white margin around my bigger prints to eliminate matting and use a metal frame - it is clean sharp and cheap but i can't seem to get aperture to cooperate - it puts the image in the corner of the paper with uneven margins (4" on one side and none or 1/2" on the others etc) even though the preview and the print dialog box shows it centered

for example-if i am trying to print a final size 24 x 21 with a 2 inch margin, i crop to 24 x say 21 x 17 and use the print driver or page setup to specify a 2" margin and image size of 17 x 20

this has usually worked great but now on my new mac pro - no deal

i use HP's driver and the dialog box allows setting the layout to oversize or crop margins, i tried both and the print is not centered and in any case the margin apertures print box allows is 1" max

also tried to change the image size in "edit with photoshop" to actually be 20 x 17 and no deal

any suggestions or where do i go to read about how aperture margins and printing works?

B. Bernardi

Have you tried the "Calibrate..." button in the print settings dialog? It will print a test sheet with alignment pointers and let you zero in on what you want.

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although i don't think this deals with large margin differences such as i have, I tried it and my z3100 is dead on zero for both left and right margins (it won't do top and bottom on roll paper)

appreciate the input though