How to Make a Monochrome Coloring Book (One-Pen Color by Number)

A monochrome coloring book hides a picture in a grid of numbered squares. The reader needs one black pen. Each number tells them which mark to draw, and the picture shows up as they go. It's a coloring page and a puzzle in one, and these books are selling well on Amazon right now.

This guide covers what a monochrome coloring book is, what the demand looks like on Amazon KDP, why it's so slow to make one by hand, and how to make a full book with answer pages in InkChamps in three steps.

What is a monochrome coloring book?

Each page is a grid of small squares. Some squares have a number in them. At the bottom of the page there's a key that says which mark each number means, for example:

• 1 means draw one slash;
• 2 means draw a cross;
• 3 means draw three slashes;
• 4 means fill the square in black;
• an empty square stays white.

The marks go from light to dark. Light parts of the picture get a single slash, and the darkest parts get filled in. So the finished page has real shading, even though it's all done with one pen.

The reader can't see the picture at the start. It shows up square by square. That's the appeal: it's a coloring page and a puzzle at the same time.

The tulip on the left becomes the numbered grid in the middle. When every square has its mark, the reader gets the picture on the right.

On Amazon you'll see these sold as monochrome mystery mosaics, one-pen color by number, monochrome pixel art or black and white color by number. They're a cousin of the multicolor mystery mosaic, where readers color coded dots with markers on a black page. Monochrome is the simpler one: one pen, white paper, nothing to bleed through.

Is there demand on Amazon?

Yes. When we searched Amazon Books for "monochrome color by number" on 11 October 2026, it returned over 1,000 results, with Best Seller badges on the first row.

Amazon Books search for "monochrome color by number", 11 October 2026.

A few numbers from that day:

That top seller went from launch to 434 ratings in under five months. Publishers don't build 20-book series in a niche that doesn't sell.

Why people like it

• It's a mystery. You keep going to find out what the picture is. A normal coloring page shows you everything up front.
• One pen is enough. No box of 24 markers, nothing to bleed through the page. It works on a train, on a plane or on the sofa.
• It's calming. Each square is a small, clear task, and it's easy to lose an hour in one page.
• You can't get it wrong. The key tells you what to do in every square. People who say "I can't draw" still end up with a real picture.
• The answers are in the back. Anyone can check their page in a few seconds.

Why it's hard to make by hand

Here's what one page took in our samples. The rose further down is 46 squares wide and 81 tall: 3,726 squares, 1,298 of them numbered. Even the simpler tulip is 28 × 33: 924 squares, 496 of them numbered.

A 20-page book with a grid like the rose means around 75,000 squares you have to get right. To make each page by hand, you would:

1. Draw or commission an original picture that still looks like something at low resolution. You can't trace someone else's pixel art and sell it.
2. Reduce it to two, three or four tones, one for each mark.
3. Shrink it to the grid size you want.
4. Decide the number for every square.
5. Draw the grid, type in every number and add the key.
6. Make the answer version with every mark drawn in.
7. Check that the answer matches the puzzle, square by square. One wrong number puts a black square in the wrong place, and a buyer will spot it.
8. Lay out every page for your KDP trim size and margins, put four answers on each answer page, and export one PDF.

Then you do it 19 more times. Most of that time goes into step 7: checking.

How to make a monochrome coloring book in InkChamps

In InkChamps you pick a theme and a style. It does the rest: it picks a different subject for each page, draws it, turns it into a numbered grid with a key, and builds the answer pages from the same grid. Because the puzzle and the answer come from the same grid, they always match.

Open the dashboard and choose Coloring → Pixel Reveal.

Step 1: Pick a theme

Type a theme, like "Garden flowers", "Wild animals", "Vintage cars" or "Space". You'll get a different picture on every page. If you're stuck, click Give me an idea.

Use Instructions if you want particular subjects. For example: "A rose, a tulip, a sunflower and a daisy. One flower per page, big and clear." You can leave it blank.

Step 2: Choose Monochrome and the number of pages

Choose Monochrome: numbered squares and one black pen. (Multicolor is the version with coded dots on a black page. We'll cover it in another post.)

Then pick how many pictures you want: 10, 20, 30 or 50. Answer pages are added at the back, four answers per page, at no extra cost.

Step 3: Pick the age group and print settings

InkChamps supports every age group, from kids to teens to adults. The age group you pick sets how complex the puzzles are:

Then set the trim size (8.5 × 11 is the usual one for KDP activity books), the print sides and the page edges. Monochrome uses Both sides by default, because a pen doesn't show through the paper the way markers do. That also makes your book thinner and cheaper to print.

Click Make pixel reveal book. Each puzzle page costs 1 credit and the answer pages are included, so a 20-picture book is 20 credits.

The book shows up in Projects while it's being made. When it's done, download the PDF. It's ready for KDP, with the puzzles first and the answers at the back.

Sample pages

This rose uses the finest grid, 46 squares across. The marks give the picture several shades of grey.

The puzzle is on the left and the answer on the right.

Here's the same rose with a bigger grid: 36 squares across and three marks. It's quicker to finish.

And a page from a test book we made with the theme "flowers", with big squares and two marks:

The key at the bottom says 1 = one slash and 2 = fill it in.

The answer page at the back of the same book. Every puzzle gets one.

Publishing it on Amazon KDP

• Ink and paper: black ink on white paper. Monochrome doesn't need color printing, which keeps your printing cost and your price low.
• Page count: KDP's paperback minimum is 24 pages. With 20 puzzles and 5 answer pages printed on both sides, you're at 25. See KDP minimum page count if you're unsure.
• Title and subtitle: use the words buyers actually search for: "monochrome", "color by number", "one pen", "mystery mosaic", plus your theme.
• Say there are answers: "Answers included" in the description helps buyers decide.
• AI disclosure: when you publish, KDP asks whether your content is AI-generated. Answer yes for the pictures.
• Cover: make it after the interior is final, so the spine width is right. Our guide on creating KDP cover pages walks through it.

Frequently asked questions

What is a monochrome coloring book?

It's a coloring book where every page is a grid of numbered squares. The reader draws the mark the key gives for each number, like a slash, a cross or a filled square, using one black pen. When every square is done, a hidden picture shows up.

Can I make the puzzles easier or harder?

Yes. In InkChamps, the age group you pick sets the complexity: bigger squares and fewer marks for kids, a fine grid and all four marks for teens and adults.

What pen should I use for a monochrome coloring book?

A black fine liner or felt-tip pen works best. Ballpoint works too. Pick a size that fits the squares: a fine liner for small squares, a thicker pen for big ones.

Are monochrome coloring books profitable on KDP?

The demand is there. The top title we found ranked #4,203 in all of Amazon Books, with 434 ratings less than five months after launch. Interiors are black and white, which keeps printing costs low.

How long does it take to make a monochrome coloring book?

By hand, each page means choosing a mark for hundreds or thousands of squares and then checking the answer against the puzzle, so a full book takes days. In InkChamps you set the theme, style and age group in a few minutes, and the whole book is put together for you with its answer pages.