Hatch & Fill
Hatch. Fill. Switch off.
The addictive new mystery coloring book for adults.
Every cell holds one code, and that code tells you two things at once: the mark to draw, and the color to draw it in. You follow it cell by cell, with no palette to plan and nothing to decide, and a picture you could not see at the start slowly rises out of the grid.
What a Hatch & Fill page looks like
It starts out looking like almost nothing: a pale grid of codes on white paper. The marks build the light and the shadow, the colors build the image, and the picture only turns up once enough cells are filled. That late arrival is the whole point of the format, and it is what makes this a mystery coloring book rather than an ordinary one.
How it works
Three things, and none of them asks you to make a decision. That is what makes it a relaxing coloring book for adults rather than a puzzle: no palette to plan, no colors to pick, nothing to get wrong.
Six marks
From a light dot to a solid fill. The denser the mark, the darker the cell, which is how a grid of pen strokes ends up with real light and shadow.
Ten colors
Black, pink, red, orange, yellow, light green, green, light blue, blue and purple. Standard colors, the ones already sitting in most gel pen sets.
One key per page
Each page carries its own small key of about twelve codes, and each code reads as one mark plus one written color name. Nothing to memorize, and every page arrives with a new set to discover.
Two ways to color the same page
Follow the codes in full and you get the color version. Ignore the color names, pick up a single pen, and the very same page becomes a monochrome drawing. Same grid, same marks, two results that look nothing alike.
Try a free coloring page first
The warm-up page is a full Hatch & Fill design, free to print, with its own key and five colors. It is the fastest way to find out whether the format is for you.
The Hatch & Fill Coloring Book
One hundred mystery pages in a single adult coloring book, printed on 8.5 x 11 inch paper and made for the gel pens you already own.
- 100 mystery pages, 8.5 x 11 inches
- Six marks and ten colors, one code giving you both
- A key on every page, so each design is its own small puzzle
- Works in full color or with one pen only
- An index with all 100 finished designs at the end
- Made for gel pens. Alcohol markers soak through and can ruin the key printed behind
Questions people ask
What is a Hatch & Fill coloring book?
It is a mystery coloring book for adults, built on a grid of coded cells. Each code stands for one mark and one color, so a single gesture places both. The marks carry the shading and the colors carry the picture, which makes the finished page look closer to a drawing than to flat color by number.
How is it different from a color by number book?
In a color by number book, a number means a color and every cell is filled the same flat way. Here the code also tells you which of the six marks to draw, so the same ten colors produce light, shadow and texture. It is the difference between filling a shape and drawing it.
Which pens do I need?
Gel pens, in the ten standard colors printed on the back cover. Please skip alcohol markers: the key of one page is printed behind the artwork of another, so ink that soaks through can make a page impossible to finish. The sets that work well are listed on the Pixelcolorist links page.
Can I color it with a single pen?
Yes. Read the marks and ignore the color names, and the same page turns into a monochrome drawing. It is the format the book grew out of, and it travels well since one pen is all you carry. If that is the part you like, the whole book built on it is 100 Color by Number Monochrome Mysteries.
About Éloi
Hi, I'm Éloi. I make coloring books on my own, one at a time, from the first sketch to the last page.
This one started with a question readers kept sending me after the monochrome book: could the marks and the colors work together on the same page? It took a lot of test pages to get the density right, because a mark that is too light disappears and a mark that is too heavy eats the cell. This is the version that finally felt good to color.
I read every message that comes in. If you color a page, send it over, I love seeing what people do with these.
Where the format comes from
Hatch & Fill is a coloring format created by Pixelcolorist and published on August 14, 2026. It grew out of an earlier one pen monochrome book, and out of a question its readers kept coming back to: what if the marks carried the shading and the colors carried the picture, at the same time?
Every Hatch & Fill book is made and published by Pixelcolorist, and sold on Amazon only. If you come across the name anywhere else, it did not come from here.