MP 6001 doesn't print black/white photos well SP C312DN does.
I printed the same photo with my SP C312DN, driver set to 600 dpi (top), and my MP 6001, driver set to 1200 dpi (bottom). The difference is very noticeable. In spite of the SP C312DN printing at a lower resolution, it looks significantly better. The SP C312DN was set to black & white (i.e. no composite black).