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Mosaci
For KDP publishers

Create KDP color-by-number books without Photoshop

Turn photos and illustrations into numbered coloring pages, build a complete interior in batches, and export print-ready files at the size Amazon expects.

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No credit card · 10 free credits every month

Free, no sign-up

Test a page from your book right now — free, no account

Upload a photo and use the real converter in your browser. Nothing is uploaded to a server — conversion runs on your machine.

JPG, PNG, or WebP · up to 12 MB
Processed in your browser, never uploaded
Use images you own or have permission to use

Pattern
Page sizeAmazon KDP paperback trim sizes
Cell size29px — smaller cells mean more of them, and more detail
Theme

The preview is the real converter — switch patterns, zoom, and inspect the color key. Exporting a 300-DPI, KDP-ready PDF happens in the Studio, free with every account.

What is a KDP color-by-number book?

A KDP color-by-number book is a low-content paperback whose interior is a set of numbered coloring pages, each paired with a color key, usually with solution pages at the back. The work is rarely the concept — it is producing sixty to a hundred pages that share one visual style, sit correctly on the trim size, and print at a resolution the press will accept. Doing that by hand in an image editor takes days per book. Mosaci Studio does the conversion, numbering, color key and export in one batch, so the effort goes into choosing the images instead of processing them.

What publishers get out of it

  • Pages render at 300 DPI on any KDP paperback trim size (8.5 × 11 in by default), with the DPI written into the file
  • Batch a folder of images with one pattern, cell size and palette across the set
  • Numbered cells generated against an automatic color key
  • Solution pages produced alongside the numbered interior
  • Export as PDF for upload, PNG per page, or ZIP for the whole batch
  • 8 color mosaic patterns and 2 monochrome mark styles, so a catalog of books does not look repetitive
  • Publish and sell what you make from images you hold the rights to
  • 10 free credits every month — enough to test a style before committing to a book

From a folder of images to a book interior

  1. Step 1

    Gather the images

    Pick a theme and collect the photos or illustrations for it. This is the part that decides whether the book is good; everything after it is production.

  2. Step 2

    Batch the conversion

    Upload the folder and set the pattern, cell size and palette once. Those settings apply across the batch, which is what gives the interior a consistent look.

  3. Step 3

    Export the interior

    Pick your KDP trim size, then take the numbered pages and answer keys as a print-ready 300 DPI PDF — with bleed and a gutter margin set from your page count — and upload it to KDP as your interior file.

Who publishes with Mosaci

Publishers building a catalog

Produce a series in one style, then switch pattern for the next title so the books stay distinct without restarting the workflow.

First-time low-content authors

Test a theme with a handful of pages on the free credits before committing the time to a full interior.

Publishers with a backlog of images

If you already have the photos and not the hours, batch conversion processes the whole set with one set of settings in a single pass.

Etsy and print-on-demand sellers

The same export works as a digital download or a POD interior — the files are not locked to Amazon.

Questions about publishing on KDP

Can I publish color-by-number books made with Mosaci on Amazon KDP?
Yes. Pages you generate from images you hold the rights to are yours to publish and sell, including on Amazon KDP, Etsy and print-on-demand stores. The license page sets out the full terms.
What page size and resolution does Mosaci export?
Any of Amazon KDP's 16 paperback trim sizes, with 8.5 × 11 in as the default, rendered at 300 DPI. The exported files carry that DPI in their metadata rather than defaulting to 72 — which is what stops a print service from treating a 2550 × 3300 px page as an oversized screen image.
Does the PDF handle bleed and the gutter margin?
Yes. The interior PDF exports with KDP bleed by default (0.125 in wider and 0.25 in taller than the trim), or at the exact trim size if you turn bleed off. The inside (gutter) margin is set from the book's page count, following KDP's published margin table. Choose the same Bleed or No bleed option when you set up the book on KDP.
Can I convert a whole folder of images at once?
Yes. Upload a folder and the batch runs with one pattern, cell size and palette setting across every page, which is what keeps a hundred pages reading as a single book instead of a hundred unrelated conversions.
Does Mosaci produce the answer pages?
Yes. Solution pages are generated alongside the numbered interior, so the back matter of the book is produced in the same pass rather than assembled by hand afterwards.
What do I need to make a color-by-number book?
Images you have the rights to, a trim size, and a page count. Mosaci handles the conversion, numbering, color key and export; you supply the images and the book concept, and upload the finished interior to KDP.
Does Mosaci guarantee my book will be approved on KDP?
No. Mosaci controls the formatting — page size, resolution and layout are set for common KDP interior specifications — but Amazon reviews every book against its own content, copyright and trademark policies. You are responsible for having the rights to every image you use and for checking the final file before you publish.

Related tools & guides

Color by Number Online

Color free color-by-number pages in your browser — phone, tablet or desktop, no sign-up.

Coloring Book Generator

Turn a whole folder of images into one print-ready book interior.

Color-by-Number Generator

Convert a single photo free, right in the browser, before starting a book.

Pricing

10 free credits every month. Buy more as a one-time purchase.

See it on a real photo

Each example shows the source image, the numbered page, the colored result and the color key made from it.

Colored Meerkat coloring page example

Meerkat Coloring Page

Colored Moose coloring page example

Moose Coloring Page

Colored Polar Bear coloring page example

Polar Bear Coloring Page

Colored Red Fox coloring page example

Red Fox Coloring Page

Browse the full gallery

Guides on this

How to Create a Color by Number Book for KDP

A production guide for color-by-number books on KDP: locking one palette, numbering consistently, building answer keys, and doing the page-count arithmetic.

KDP Coloring Book Interior Specs and PDF Setup

KDP coloring book interior specs: trim size, bleed, margins by page count, 300 DPI pixel sizes, and PDF export settings, plus a pre-upload checklist.

Coloring Book Interior Design: Layout & Margins

How to build a professional coloring book interior — margins, bleed, image sizing, page order, front and back matter, and print testing.

How to Create a Coloring Book From Photos

The full workflow for turning a photo collection into a finished coloring book: selecting, converting, standardising, assembling, and preparing for KDP.

All guides

Start building your book interior

Convert a photo without an account to see the result. Creating one is free and takes a moment — it comes with 10 credits every month and no card.

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