(Yesterday, 07:09 PM)bringoutthegimp! Wrote: ...snip....
When I print the photo at 300x300 dpi it prints very small on the paper (~3.5" x 2.25"). When I print at 600x600 dpi it seems to prints at the correct dimensions (~7" x 4.7"). When I print at 1200x1200 dpi it prints only a small portion of the image (very large), since the majority of the image would appear off of the page. In each case, it would seem that the image should actually print at 7.0" x 4.692" since that is what I selected...yet, these different sizes are the result. It appears that the DPI setting selected in the Gimp Print option is dictating the image size, rather than the Print Size that I have selected for the file.
I assume that the MacOS Gimp 3.0 print dialogue is the same as linux (dangerous assumption) Nothing that I can see that has changed since Gimp 2.10 This a Gimp 3.0 RC3 appimage.
(1) Have you set the page size to A3 ? There have been remarks in the past that Gimp will only use A4 but the available sizes do come from the printer driver.
(2) You are correct, the print resolution will override the Image print resolution. In this one I put on 300 ppi which changed to 305.3 ppi to fit the page. It should not crop anything, ( eg 200 ppi is not possible) and increasing the ppi or changing the width / height to set a size works here.
Then just the usual: What does http://localhost:631 say about printer settings ?