Problem printing A2 @ 1440ppi on Epson SC-P900

It’s a very good question. Generally, how I understand it is that it is not just about the paper type, it’s affected by quality control along the entire image processing chain. When setting Output Resolution in the Epson printer driver, generally:

720–1440 dpi. Should look OK with average images on most papers, especially matte. Canvas could go down to 720 dpi. This has to do with how much resolution the media can actually hold; for example canvas is so rough you won’t be able to see the difference between 720 dpi and higher settings.

1440–2880 dpi. 1440 is usually OK for almost everything. 2880 dpi can potentially reproduce more detail and sharpness, but this depends on two things: The quality of the image, and the quality of the media. The image must be captured with a sharp lens, with perfect focus, no motion blur, and enough of the original pixel dimensions (for example, if you crop or enlarge too much there might not be enough pixels in the print area to reproduce 2880 dpi at the final print size). The image must be processed in a way that properly preserves original detail (e.g., not overdoing noise reduction) and not going too far (over-sharpening until there are visible halos). And the media must be at the high end of the scale for reproducing detail, such as Epson Ultrasmooth matte or one of the more expensive glossy papers. Less smooth papers, such as those with Rough, Textured, Velvet, or Watercolor in the paper name, may not reproduce much additional detail over 1440 dpi.

If you want to keep it simple (this is what I do, since I don’t have the very best equipment), just leave Resolution blank in Lightroom Classic, the Epson driver set to 1440 dpi, and the High Speed option enabled, unless it’s a special image on high quality media and then you can set the Epson driver to 2880. You can run your own tests to find out if you can see any difference with your images and papers on 1440 vs 2880; if not, leave it on 1440 dpi.

There is even more to print quality than just those factors; for example disabling High Speed means the print head will lay down ink unidirectionally (slower) instead of bidirectionally; on the old Epson printers that could potentially improve print quality a slight bit more but some say High Speed is just fine today. Also, there are debates on the web about whether the Finest Detail option makes a difference for photos (some say it is only for graphics such as vector art).

Part of my understanding comes from the heading “Printer-Specific Settings” starting on page 181 of the book The Digital Print by Jeff Schewe. (His book makes a case for Finest Detail making a difference with photos, but again only if the image resolution, image quality, and media are high enough quality to support what it does, and only if High Speed is disabled.)

Cheers Johan, you are of course right 720 is quite enough!

By @Hans Von Bongo Papster

Like I said, even 720 ppi is too high, and probably way more than the number of pixels in your image. You would need an image of 23.4 x 720 pixels = 16,848 pixels wide and 16.5 x 720 pixels = 11,880 pixels high. That's still 200 Mpixel! Use 360 ppi.