Colour by number: how it works, and who it's for

JCBy Julien CornilleCo-founder and publication director, Memory Pencil

The colour by number from your childhood, but made from your own photos. How we split an image into numbered zones, who it speaks to, and what changes compared with the classic colouring book.

Colour by number, you probably picture it already: a grid of zones, each marked with a number, and a legend that says which colour goes in which number. You fill it in zone by zone and the image appears. What we do at Memory Pencil is exactly that, but from your family photos. Here is how we go from a photo to a numbered colouring page, and who this format suits best.

The idea: two pages per photo

Just like the colouring book, each photo becomes two pages. On the left, the model page: your photo simplified into flat colour areas, each zone carrying its number. That's the guide, the one you look at to know which shade goes where. On the right, the page to colour: the same zones, but empty and numbered, with a legend that matches each number to its colour. You colour by following the numbers, and the memory comes back.

How we split a photo into zones

This is the step that decides everything. We first redraw the photo as a flat-colour illustration, then trace it in black line art: every closed shape in the drawing becomes a zone to colour. Too many zones and the page becomes an unreadable puzzle. Too few and the image turns into blobs. The sweet spot is zones large enough for a marker, numerous enough to recognise the face. Each zone then takes the closest colour from a fixed box of 24 pencils, the same for the whole book: a sky blue stays the same sky blue from one page to the next. The number sits where the zone is widest, and each page's legend lists only the colours it needs, numbered from 1 up, with no gaps.

What sets it apart from the classic colouring book

Both start from your photos, but the way you colour changes. The colouring book gives you an outline page to fill freely, with whatever colours you like: total freedom, including the freedom to get it wrong. Colour by number imposes a colour code to follow, zone by zone. It's more structured, more reassuring, and the result really looks like the original photo. Neither is better, they just suit different moments.

Who it's for

• Children, from around 4 or 5: the numbers guide the hand, there's no fear of doing it wrong, and watching the image reveal itself is hugely satisfying.
• Adults who like stress-relief colouring: following a colour code is restful, you let yourself be carried without deciding every shade.
• As a gift: you recognise the photo right away, and there's something to do with it, not just to look at.

Printed or digital, and what it costs

Same formats and same prices as the colouring book. As a bound book, free delivery: £19.99 for 6 photos, £34.99 for 12 photos, £51.99 for 24 photos. Every format and the order page are on personalised colour by number. As a downloadable digital version, you get the same colour-by-number book as a PDF from £5.99, to see how your photos turn out before ordering the book. And if the PDF wins you over, you have 30 days to have it printed as a real book.

Colour by number is the same keepsake photo as the album, but with instructions: follow the numbers and the image comes back.