Hi Larry,
I was hoping for more flexibility in setting dpi as I have in Photoshop.
I have to say QU is smarter than PS in this respect and helps to prevent you "screwing up"
You may already be aware, but 600ppi is no good for an Epson printer where the native resolution is 720ppi that is why QU reads that value from the driver.
Printer drivers expand their print resolution when set to borderless and this is what QU reports and uses to interpolate to, so just let QU do its thing.
QU has a settting (Edit preferences, Print and page formatting) to disable "overspray/expansion" but the printer resolution remains the same (610ppi for you).
The purpose of this feature is to avoid the driver cropping off portions of the image around its perifery. However, unless the paper feed is spot on, slithers of white may appear at some edges of the print.
Regarding QU's superior interpolation and design philosophy look at the web site
http://www.ddisoftware.com/qimage-u/technology.htmFrom the very beginning QU was designed to make relatively large high quality prints from 3Mp or 6Mp images. Cameras have improved since then but the principle of interpolating to the printer native resolution with Mike's latest Fusion interpolation is still very relevant.