It not only depends on the image content, but how you send the image to the printer. Print engines can apply nearest-neighbor interpolation which results in vi

It not only depends on the image content, but how you send the image to the printer. Print engines can apply nearest-neighbor interpolation which results in visible, blocky pixels. If they'd upsampled the image with lanczos or another higher-quality algorithm before sending it to the printer, it would have looked like it was just a touch out of focus.