Each retailer has slightly different requirements for cover dimensions, DPI, file format, and bleed. Bellwether generates the correct file for each retailer automatically. This article documents what gets produced so you can verify against a retailer's current requirements yourself, plus the print-specific details that trip up first-time print authors.

Where to export

In the Cover module, click Export in the top-right. A panel opens with one row per retailer you have connected, plus an All retailers option.

Per-retailer export produces a single file sized for that retailer. All retailers produces a ZIP with every variant, named by retailer.

Ebook covers and print covers are separate exports. Ebook exports only include the front cover. Print exports include front, spine, and back as a single wraparound PDF sized for your trim, page count, and paper stock.

You can also trigger exports from Publish → Review when preparing to submit; in that context, the right exports happen automatically for the retailer you're publishing to.

Ebook cover specs

All ebook exports are at 72 DPI. Retailers don't care about print DPI for ebook covers; what matters is pixel dimensions and colour space.

Aspect ratio

Most retailers want a 1.6:1 ratio (height:width). Amazon allows up to 1.8:1. Apple enforces 1.5:1. Your cover in Bellwether stays at 1.6:1 by default. When exporting for Apple, Bellwether either crops (if you've positioned art safely inside the trim-safe zone) or adds letterbox bars (if you haven't). You can see which will happen in the Export panel before confirming.

File size

• Amazon: max 50 MB per file.
• Apple: max 2 GB.
• Kobo: max 10 MB.

Bellwether's ebook exports are usually under 2 MB. If yours is larger, it's because you've used a high-detail source image; the quality setting under Export will reduce size at the cost of some detail.

Print cover specs

Print covers are wraparound PDFs sized by trim and page count. Bellwether calculates spine width from your book's final page count and paper weight.

If your book page count changes after you export, the spine width will be wrong. Bellwether will refuse to export a print cover if the current page count doesn't match the cover's stored page count. Regenerate before exporting.

Spine width

Spine width depends on:

• Final page count of the interior PDF
• Paper stock (Bellwether uses the retailer's default: 55 lb cream for most, 50 lb white for some imprints)
• Binding (perfect bound assumed; saddle-stitch and hardcover have different calculations)

The formula per paper stock (approximate):

• 55 lb cream: pages × 0.00225 inches
• 50 lb white: pages × 0.00200 inches
• 60 lb cream: pages × 0.00260 inches

You can override the paper weight under Cover → Print settings if your retailer is using a non-default stock, or if you're using a boutique printer.

Bleed

All print exports include 0.125 inch bleed on all four sides. This means your background extends 0.125 inches beyond the trim edge on every side. The trim marks and bleed zone are included in the PDF metadata so the printer knows where to cut.

If you're uploading to a printer that doesn't use our retailer presets, export Generic print PDF. You'll be asked for trim size, bleed, and page count explicitly.

Safe zones

Print covers have three zones:

• Bleed. Outside the trim line, 0.125 inches. Art here will be cut off.
• Trim. The actual edge of the finished book.
• Safe area. 0.25 inches inside the trim. Important text (title, barcode) must fit inside this.

Bellwether overlays these zones in the print preview. Anything in the bleed zone is for extending background colours only; don't put logos or title text there.

Colour space

Ebook covers are sRGB. Print covers are CMYK. Converting between them always shifts colour. Bright saturated blues, reds, and oranges in sRGB will look duller in CMYK.

If your cover has critical colour moments, export a CMYK proof and check it before finalising. Bellwether's preview in the Cover module is sRGB by default; the Print preview toggle switches to a simulated CMYK view.

For best CMYK results:

• Avoid pure digital colours (RGB 255/0/0, for example). Print can't reach them, and they'll look dull.
• Stick to colours that fall inside the printable gamut. Bellwether warns you with an out-of-gamut indicator on the Colour picker if you pick a problematic colour.
• If your cover was generated by the AI, the generator already favours printable colours.

ISBN barcode

Print cover exports include the ISBN barcode on the back cover automatically if you've entered an ISBN under Publish → Metadata → ISBN.

The barcode uses EAN-13 format, which is what retailers expect for books. It's placed in the lower-right corner of the back cover by default. Under Cover → Print settings → Barcode, you can:

• Move the barcode (only within the safe area).
• Resize it (within retailer-acceptable bounds).
• Change the background (white is default; some covers need a white rectangle behind the barcode so the scanner can read it against a dark background).
• Include the price above the barcode (optional; mostly used for brick-and-mortar distribution).

To hide the barcode (for a proof copy, or if you're adding it elsewhere), toggle off Include barcode in the export panel.

File naming

Exported files are named automatically:

• Ebook: {book-title}_{retailer}_ebook.jpg
• Print: {book-title}_{retailer}_print.pdf

For the "All retailers" ZIP, the structure is {book-title}_covers.zip/{retailer}/{file}.

You can override the file name prefix under Cover → Export settings → File name.

Export history

Every export is logged. Find past exports under Cover → Export history. Entries include:

• Retailer and format
• Timestamp
• File size
• Cover version used
• Page count (for print exports)

Click any entry to re-download, or regenerate if your cover has changed since.

Common edge cases

My print cover was rejected for spine width. Your page count changed since the cover was generated. Regenerate the print cover from the current page count. Bellwether prompts you to do this when it detects the mismatch.

The preview looks fine but the export is blurry. Uploaded art is scaling past its resolution. Go to Cover → Imagery and check the source resolution. Re-upload a higher-res source. For print, anything below 300 DPI at final trim size will print soft.

KDP says my cover is too small. Unlikely on auto-export. If you uploaded your own art, the source may have been below 2000px. Re-export at full dimensions.

My colours look off on the printed proof. sRGB to CMYK always shifts. Check the CMYK preview in the Cover module and adjust saturation if the difference is large. Saturated reds and oranges are the biggest shifters.

I need an embedded colour profile. Bellwether embeds sRGB IEC61966-2.1 in ebook exports and US Web Coated SWOP v2 in print exports. These are the most widely-accepted profiles. If your printer requires a specific profile, contact support; we can produce a custom export for Studio plans.

The barcode is blocking my back cover art. You can move the barcode within the safe area (under Cover → Print settings → Barcode) or add a white panel behind it to preserve your art design. You cannot remove it if you've entered an ISBN and plan to submit to a retailer that requires a barcode.