Under the heading 'Prints' at top of page, go to 'print/Image interpolation". The options for final print sharpening are 'smart sharpening', 'normal sharpening' plus a slider that takes you from off, default, med to high.
What I find interesting about Qimage is the great choice of interpolation algorithms. I've been using the default 'Pyramid' algorithm which appears to be the best quality, but I've never bothered comparing any of them on actual prints. The list of options (with a 'quality' no. in parenthesis) is as follows:- Pyramid (10), Vector (
, Lanczos (7), Bicubic (6), Mitchell (5), Triangle (3), Hermite (3) and Bell (3).
Pyramid also has a slider that goes from smoother to sharper. Again, I've never bothered comparing the difference on prints. Maybe I should.
I'm puzzled that I cannot get Qimage to interpolate ppi to 720. It's always 360ppi (on my Epson 7600) with settings at maximum micro detail. But I have noticed that in certain circumstances it has interpolated an image to 720ppi in the past, but I can't remember what the conditions were. Not that it really matters. The great thing about Qimage is that it does all the work. The default settings have always seemed to be very acceptable to me.