How to Create AI Art for Book Covers: Sizing, Bleed, and Format Requirements

How to Create AI Art for Book Covers: Sizing, Bleed, and Format Requirements

Using AI-generated art for book covers is practical and increasingly common, but book cover printing has specific technical requirements that are completely unlike screen or wallpaper use. Resolution, color mode, bleed, and file format requirements all differ from digital display standards, and getting them wrong produces either a rejected print file or a cover that looks visually different in print than it did on screen.

This article covers the specific technical requirements for self-publishing platforms (KDP and IngramSpark), the setup that applies to all book cover work, and the most common failure points that cause file rejection.

Core Technical Requirements for Book Cover Print Files

Resolution

Print book covers require a minimum of 300 DPI (dots per inch) at the final print size. This is different from screen resolution: a 1920x1080px image displayed on a monitor is effectively 72-96 DPI at screen size, which is fine for screens. At print size, 1920x1080px at 300 DPI produces a physical image of approximately 6.4 x 3.6 inches, which is too small for most standard book covers.

For a standard 6 x 9 inch book cover front, you need at minimum 1800 x 2700px at 300 DPI. Including bleed (see below) pushes this to approximately 1950 x 2850px. Full wrap covers (front + spine + back) are significantly wider and require proportionally larger source images.

AI art generated at Midjourney's standard upscale resolution (typically around 1024-2048px on the long edge) is often insufficient for full-size book cover print without additional upscaling. Plan to upscale AI outputs to at least 300 DPI equivalent for the intended cover size before submitting.

Color mode: RGB vs CMYK

Digital screens display in RGB (Red, Green, Blue). Commercial printing uses CMYK (Cyan, Magenta, Yellow, Black). Colors that look vivid on screen in RGB sometimes appear noticeably duller or shifted when converted to CMYK for print, because the CMYK gamut is smaller than RGB for certain saturated colors (particularly bright blues, vibrant oranges, and neon tones).

Platform-specific guidance:

• KDP (Kindle Direct Publishing): KDP accepts RGB PDF files and performs its own CMYK conversion. Their guidance explicitly says to submit in RGB rather than converting to CMYK yourself, because their conversion is calibrated for their specific printing process.
• IngramSpark: IngramSpark recommends PDF files with CMYK color mode. For IngramSpark covers, convert to CMYK in Photoshop (Edit > Convert to Profile > choose a CMYK profile) before exporting your PDF, and do a soft-proof check (View > Proof Colors) to see what the CMYK conversion will look like.
• Local printers: Always ask. Some accept RGB; most prefer CMYK for offset or digital printing. Ask for their ICC profile if possible to do an accurate soft proof.

File format

• KDP: Accepts PDF, TIFF, and JPEG. PDF is the recommended format for covers because it preserves embedded fonts and color profiles accurately.
• IngramSpark: Requires PDF-X/1a or PDF-X/4 format. These are print-specific PDF standards that embed all fonts and color profiles. Standard PDF exports from Photoshop or Illustrator can be configured to meet these standards in the export settings.
• TIFF: Accepted by most platforms and preserves full image quality without JPEG compression. Larger files than PDF or JPEG but appropriate for high-quality covers.
• JPEG: Acceptable for some platforms but introduces compression artifacts. Use at 95%+ quality if JPEG is the only option and check for artifacts in smooth gradient areas.

Bleed Setup

Bleed is the area beyond the final trim edge of the cover that extends the artwork past the cut line. It exists because physical cutting of printed pages is not perfectly precise: the cut can be off by 1-2mm. Without bleed, a slightly off-cut produces a thin white border at the edge of the cover where the background paper shows through. With bleed, the artwork extends past the cut edge, so any cut variation is still within printed artwork.

Standard bleed requirements

• KDP: 0.125 inches (3.175mm) bleed on all sides.
• IngramSpark: 0.125 inches (3.175mm) bleed on all sides.
• Most commercial printers: 3mm bleed is the industry standard; some require 5mm.

Setting up bleed in Photoshop

1. Create a new document at the final cover dimensions plus bleed on all sides. For a 6 x 9 inch cover at 300 DPI with 0.125" bleed, the canvas is 6.25 x 9.25 inches (adding 0.125" to each side).
2. Use guides to mark the actual trim lines (the non-bleed edge) at 0.125" from each edge. Keep all important content (title, author name, imagery) within a safe zone that is at least 0.25" inside the trim line.
3. Extend all background artwork and color to the full bleed canvas edge, including the extra 0.125" on each side.

What goes in the bleed zone vs the safe zone

• Bleed zone (outside trim line): Background color, texture, and art that continues beyond the cover edge. Nothing text or critical imagery.
• Safe zone (inside trim line, at least 0.25" from trim): All text (title, author name, subtitle), spine text, barcode, logo, and any imagery that must not be cut.