Artwork is too low resolution

DPI is a property of the printed size

An image has a fixed number of pixels. Its resolution in print — dots per inch — depends on how large it is printed: the same picture is sharp on a small panel and soft on a large one. Cover artwork should reach 300 DPI at the size it will actually print.

To work it out, divide the image's pixel width by the printed width in inches. A 6" front cover at 300 DPI needs an image 1800 pixels wide before bleed, and a little more to cover it.

Why upscaling does not help

Enlarging an image in an editor adds pixels by interpolating between existing ones. The number goes up; the detail does not. A small image enlarged to the right pixel count still prints soft, and it may now look smeared rather than merely low-resolution. AI upscalers do better on some images and invent detail on others — check the result at full size before trusting it.

Where low resolution comes from

Most low-resolution covers trace back to one of these:

• Images saved from a web page or social media, which are compressed and sized for screens.
• Exporting a design at screen resolution instead of print resolution.
• Cropping a small part of a photograph and enlarging it to fill a panel.
• Stock images downloaded at a small or medium size.

Measuring yours

The cover builder reports the effective DPI of each image as you place it, using the panel's real printed size. It is the number to watch while choosing artwork, not just at the end.

Resolution of interior images

The same arithmetic applies inside the book. A photograph printed across a 6" page needs about 1800 pixels across to reach 300 DPI. Screenshots are a frequent weak spot in non-fiction: a screen capture printed large prints soft, and it is usually better to print it smaller and sharp than large and blurred.