Xara Requests, next try

[Acorn]

Well, printing has to be down to the printer and its gamut and ink bleed.

If, however, you are asking about a source PDF, I tried a a linear page gradient and exported @9600dpi with no complaints.
I only managed to see banding at 6400% scaling of the PDF.
I have no idea what dpi a PDF can handle.

Acorn

[handrawn]

although the theoretical size of a PDF file can be very large indeed, according to spec I have you are limited to about 5m [tad under 200 inches] if you use illustrator/acrobat-distiller which is a fair number of pixels... dpi is just a packing ratio, n’est-ce pas?