# How to Make a Colour-Blind-Friendly, Print-Safe Map with Patterns

Add diagonal hatching or dots to a painted country so your map still reads correctly in black-and-white print and for colour-blind viewers.

> Editor: https://ohmymaps.com/ · Versão em página: https://ohmymaps.com/blog/colour-blind-friendly-map-patterns/

Colour alone is a fragile way to carry a map. Print it in greyscale and two
mid-tones collapse into each other. Show it to a colour-blind reader and
red/green or blue/purple pairs that look obvious on your screen can be
indistinguishable. Neither problem is rare: printing in black and white and
colour vision deficiency both affect a meaningful share of any real audience.

[Oh My Maps!](https://ohmymaps.com/) has two fill patterns built for this,
and they work alongside colour rather than instead of it.

![A painted world map where several countries carry diagonal hatching or dot patterns on top of their fill colour, distinguishable from solid neighbours in greyscale](/blog/posts/colour-blind-friendly-patterns.svg)

## The two patterns

Diagonal hatching and dots. Both belong to the **brush**, next to the colour
picker: choose a pattern, then click a country, and it gets colour and
texture together in one action. A country can also be textured after the
fact from its right-click menu, without touching the sidebar.

The tile itself is a pale tint of your chosen colour, with the hatching or
dots drawn at full strength on top. That is a deliberate choice, not the
obvious one: a fully transparent tile would let the ocean colour show through
between the strokes, so a hatched country would read as unpainted water in
places. The pale-tint tile keeps the country reading as "the blue one" at a
glance while still being unmistakably different from a solid neighbour of the
same colour.

<div class="cta">
  <p><strong>See it on your own map.</strong> Paint a country, then apply a pattern from the brush and watch the texture follow the colour.</p>
  <a class="cta-button" href="https://ohmymaps.com/">Open the editor</a>
</div>

## Where it helps most

- **Two adjacent countries in similar hues.** A shared border between two
  close blues is hard to see; give one of them hatching and the border reads
  instantly, even before anyone notices the colours are different.
- **A map that will be photocopied or printed on a mono printer.** Test it by
  looking at your map with saturation turned all the way down. If two regions
  still separate, the pattern is doing its job.
- **A "third tier" on a travel or status map**, where you have run out of
  colours that stay distinct from each other but still want one more legible
  category. Pattern plus colour buys you that category without adding a
  fourth hue nobody can tell apart from the third.

## The ocean has its own pattern

Separately from country fills, the ocean can carry its own pattern too, drawn
as a second, translucent layer over the water colour. It is the cheapest way
to make land stand out from sea without touching a single country's fill,
and it is worth trying before reaching for a darker ocean colour.

## What patterns do not do

**Patterns only apply in manual painting mode.** Switch the map to **Data**
mode for a choropleth and the pattern control disappears from the sidebar:
in data mode, colour comes entirely from the scale you chose, and every
country's fill is solid. This is not a bug to work around; a choropleth's
entire point is that colour intensity maps to value, and a hatched country
would break that mapping without adding real information. If you switch back
to manual mode later, any pattern you had set is still there, waiting.

**Colouring randomly always produces solid fills.** The random-colour tool
(covered in
[how to make every country a different colour](/blog/random-colour-map-every-country-different/))
skips patterns on purpose, because its whole point is a quick, uniform-looking
reference map.

## Export carries the pattern with it

Patterns are drawn as SVG `<pattern>` definitions inside the map itself, not
as an effect layered on afterward, so they survive into every exported
format exactly as painted: PNG, JPEG, WebP and SVG all carry the texture, at
any resolution up to 8000 px. There is no separate "flatten for print" step
and nothing to double-check after export.

## Next steps

- [The full tour of the editor](/blog/how-to-make-a-custom-world-map-online/)
  covers painting, colours and export end to end.
- [A map of countries you have visited](/blog/map-of-countries-visited/) uses
  patterns to keep a "transited" tier legible next to "lived in" and
  "visited".