I just opened this Nikon supplied image in Photoshop to see the Camera Data. See the attached screen shot.
At this point we don’t know if the photo was shot as a JPEG (and was what compression level, color space, etc.) or as non-compressed, lossly compressed, or lossy compressed 12 bit or 14 bit per channel NEF file, and if it was originally a NEF, how it was processed. The original was processed in Capture NX 2.3.0 W software and what level of JPEG compression (or possibly multiple JPEG compressions were used to prep the file for internet distribution.
For Epson printers: At 360ppi the non-interpolated print size is 20.444 x 13.644 inches, but as been proven to most people’s satisfaction the Epsons can do a damn fine job with Luster and gloss papers with files @ 180ppi and that yields a 40.889 x 27.289 inch print – but of course how good the print is will depend on the skills of the person making the print.
If you print at 300 dpi (Canon and I believe HP) you get a 24.533 x 16.373 inch print. With my Canon iPF 6300 imagePROGRAF I feel the bottom limit before start to see printing process artifacts is in the 200-225dpi range.
I really want to know both the image processing and JPEG compression parameters. I suspect some fine detail is being lost in the JPEG compression process. As the late Bruce Fraser pointed out “Difference is detail” and both JPEG compression and using only 8 bit per channel (required by JPEG compression) both forcefully eliminates close differences.