Why Your PDF Looks Fine but KDP Still Rejects the Cover
KDP rejects PDF cover files even when they look fine? Check page size, white borders, crop marks, template lines, hidden objects, fonts, images, and export settings.
If KDP rejects PDF cover files even when they look fine, do not keep exporting the same PDF and uploading it again. A KDP PDF cover rejected after export can still have a file problem. KDP is not only looking at the design on screen. It is checking the final PDF file you submit.
A PDF can look normal in Canva, Preview, Acrobat, or KDP Previewer and still contain problems KDP cares about: wrong page size, white borders, crop marks, leftover template lines, hidden objects, transparency issues, missing embedded fonts, soft images, comments, placeholder text, or converter-added margins.
If you are not sure the problem is really PDF-specific, start with the broader Canva cover rejected by KDP checklist. This article is narrower: it is for the moment when the cover PDF looks okay, but KDP still rejects the cover or shows a preview problem.
KDP's Paperback Submission Guidelines mention requirements such as embedded fonts and images, flattened transparent objects, no crop marks or trim marks, no comments, no invisible objects, and no placeholder text. KDP's paperback cover guidance also tells authors to remove crop marks, color bars, template text, PDF creation guides, and software references before upload.
That means a PDF can fail for two different reasons:
Problem type
What it looks like
Example
Visible problem
You can see it when you open the PDF
White border, crop marks, template line, shifted cover
File-structure problem
The PDF may look normal, but KDP reads something inside the file
Hidden layer, invisible object, comment, transparency, missing embedded font
KDP Previewer is useful, but it is not final approval. KDP's formatting guidance treats preview as one review step. If a later review email rejects the cover, read that email and recheck the final PDF.
Before checking layers or export settings, confirm the page size of the actual PDF you uploaded.
For a KDP paperback, the PDF page size should match the current full cover size: back cover, spine, front cover, and bleed in one file. If the PDF is A4, Letter, front-cover size, or an old cover size, KDP can reject it even if the artwork looks polished.
Check this:
Where to look
Acceptable
Warning sign
What to fix
PDF properties
Page size matches the current KDP full cover size
PDF is front-cover size, A4, Letter, or an old size
Fix the source size or export route
KDP template
Current template matches the exported PDF
Template edges, spine, or barcode area do not line up
Generate a current template and re-export
Converter output
Final PDF preserves exact dimensions
Converter adds margins, scaling, zoom, or default page size
Use another route or inspect the output before upload
A JPG-to-PDF case shows this well. The user was trying to create an exact-size PDF, but different tools added margins, scaling, A4 sizing, or unexpected zoom. The user eventually found a path that produced the right PDF size. The broader lesson is simple: check the final PDF page size, not only the source image or design.
Next, inspect the PDF visually at full page view and zoomed in around the edges.
Where to look
Acceptable
Warning sign
What to fix
Outside edges
Artwork reaches where it should, with no unexpected white strip
Thin white border appears after export
Return to the source file and fix bleed/export scaling
Corners
Corners are filled when artwork should reach the edge
Corners show paper color or transparent gaps
Extend artwork or fix export route
Crop / trim marks
Final upload PDF has no marks
Crop marks, trim marks, printer marks, or color bars are visible
Export a clean PDF without marks
Template layer
No template text, red/blue guides, labels, or software references
KDP template is still visible
Hide or remove the template layer
Cover order
Back, spine, and front appear in the correct order
Barcode area or back cover appears on the front side
Re-align to the KDP template
A white border can mean missing bleed, export scaling, or a PDF route that changed the page. If KDP specifically mentions 0.125 or the trim line, use the KDP cover bleed guide. If the PDF itself is the wrong size, fix size first.
Some PDF problems show up only after upload or preview.
KDP's submission guidance calls out embedded fonts and images. If text or images are not embedded or render differently, the local PDF can look fine while KDP reads or renders it differently.
Use this check:
Where to look
Acceptable
Warning sign
What to fix
Text rendering
Text looks the same in multiple PDF viewers
Font changes, text shifts, text disappears, or spacing changes
Re-export, embed fonts, or simplify text
Image rendering
Images stay sharp enough for print
Image looks soft, pixelated, compressed, or missing
Replace low-quality image and export again
Effects around text
Shadows and overlays stay stable
Effects shift or hide text in Previewer
Simplify effects or test a flattened PDF
Back cover copy
Blurb and author bio remain readable
Thin text becomes faint or jagged
Use cleaner text styling or higher-quality export
Do not fix a font or image problem by stretching the PDF. Fix the source file and export a new PDF.
This is the part that makes “but it looks fine” frustrating.
A PDF can include objects you do not notice: hidden layers, invisible boxes, comments, old template data, transparent shapes, or leftover elements outside the visible design. KDP may still read those objects.
One hidden-layer case fits this pattern: the PDF reportedly looked normal locally, but KDP flagged text or objects outside margins. The user later said support identified hidden layers or data, and cleaning the file helped. Treat this as one troubleshooting path, not proof that every PDF rejection is caused by hidden layers.
Check for these issues:
Where to look
Acceptable
Warning sign
What to fix
Hidden objects
No invisible boxes, old guides, or off-page elements remain
KDP flags objects/margins you cannot see
Clean the source file or rebuild from a clean file
Comments / annotations
None remain in the upload PDF
Comments, notes, or review annotations exist
Remove comments before export
Placeholder text
No template wording remains
Template labels or placeholder words remain
Remove before export
Transparency
Transparent objects render consistently
Shadows, overlays, or translucent elements shift/disappear
Test a flattened PDF
Layers
Final file is simple enough to render consistently
Objects appear/disappear between viewers
Flatten, simplify, or rebuild
If you cannot find the object KDP is flagging, start with the simple cleanup: remove comments and annotations, delete old template layers, check for invisible or off-page elements, and export a fresh PDF. If the file still behaves strangely, rebuild from a clean source instead of trying to rescue the same PDF.
Canva's flattened PDF guidance can be useful when layers or transparency might be the problem. But flattening is only a test. After flattening, inspect page size, edges, text, and image quality again.
Canva is not the default cause. KDP reviews the final PDF.
If the PDF came from Canva, keep the check focused on the exported file:
Canva export area
Acceptable
Warning sign
What to fix
PDF type
PDF Print used as a print-oriented starting point
PDF Print treated as automatically KDP-ready
Inspect the final PDF before upload
Crop marks and bleed
Bleed used during design; final upload is clean
Crop marks or guide marks appear in the upload PDF
Export a clean final file
Flattened PDF
Tested when layers/transparency may be an issue
Treated as a universal fix
Compare flattened output carefully
Exported page size
Matches the KDP full cover size
Canva source looks right, but PDF properties are wrong
Fix source size/export route
Canva's download file type guidance describes PDF Print as a print-oriented option. That is useful, but it does not make the file automatically ready for KDP.
If you need the full Canva setup process, use the Canva to KDP paperback export guide. This article assumes you already exported the PDF and now need to inspect what KDP received.
If you only have a front cover but the design still works, convert it into a full paperback cover before starting over. If you lost the source file, cannot confidently remove hidden/template objects, or need a new design direction, the KDP Book Cover Generator can help you create a new KDP cover draft from a cleaner starting point.
Do not keep uploading the same PDF and hoping KDP reads it differently. Find the first mismatch, fix it in the source or rebuild, then export a new clean PDF.
Because KDP checks the final PDF file, not only the visible design. The file may have the wrong page size, hidden objects, crop marks, template text, transparency issues, missing embedded fonts, low-quality images, or converter-added margins.
No. PDF Print is a useful print-oriented starting point, but you still need to check the final PDF page size, bleed, safe area, visible marks, fonts, images, transparency, and hidden objects.
No. KDP's submission guidance says submitted files should not contain crop marks or trim marks. Use guides while designing if they help, but upload a clean final PDF.
No. Flattening can help test some layer or transparency issues, but it does not fix wrong page size, missing bleed, unsafe text, barcode overlap, low image quality, metadata issues, or policy issues.
Read the review email and follow the exact issue it names. Previewer is useful, but it is not a final approval guarantee. If the email mentions PDF objects, marks, text, images, or file quality, inspect the final PDF again.
Fix or rebuild the source file when the PDF structure or page size is wrong. Resizing a finished PDF can distort the cover, move the spine or barcode area, reduce image quality, and hide the real problem.
