Colors, gradients and color blindness
Every board in Hex is built from a gradient: colors that blend smoothly from one to the next across the honeycomb. This page explains what that means, why some boards feel so much harder than others, and how Hex works for players with color blindness.
What a gradient is
A color on a screen can be described by three things:
- Hue: where it sits on the color wheel (red, orange, yellow, green, blue, purple).
- Lightness: how close it is to white or black.
- Saturation: how vivid it is, from grey to full color.
A gradient changes one or more of these steadily from one place to another. In Hex, each corner or edge of the board is anchored to a color, and every hex in between gets the blend for its position. When a hex is out of place, its color breaks that steady change, and that break is what you are looking for.
Why some boards are hard
Small steps. The more hexes a board has, the smaller the change from one hex to the next. On a large board with only a short range of colors, neighbours can differ by a sliver.
Hue changes are harder than lightness changes. People are very good at noticing "lighter" and "darker", and less good at noticing a slight shift in hue at the same lightness. That is why the later worlds of Spot and Swap lean on hue differences.
Some colors are closer than they look. Human eyes are much more sensitive to differences in greens and yellows than in deep blues and purples. Two blues that measure as far apart can look nearly the same. Hex builds its gradients in OKLab, a color model designed around human vision, so the steps feel even to your eye rather than just being even in the numbers.
Your screen matters. Screen brightness, night-shift modes and blue-light filters all squeeze the range of colors you can see. If a board feels impossible, try it with the brightness up and the filter off.
Color blindness and color assist
About 1 in 12 men and 1 in 200 women have some form of color vision deficiency. The most common kinds make it hard to tell certain reds, greens, browns and oranges apart. A puzzle built on color differences could easily lock these players out, so Hex has color assist palettes.
Color assist swaps the game's colors for gradients built to stay distinct for the common kinds of color blindness: blue to grey to yellow across the board, and dark to light down it. Those two directions (blue against yellow, and lightness) are the ones the common color blindnesses leave intact, unlike red against green. Turn it on in Settings → Color assist. Hex also has larger text, reduced motion and screen reader support; the accessibility statement has the details.
Try it
The easiest way to get a feel for all this is to play: start with the Swap guide, or jump straight into Swap or Spot.