Colour on a sign is doing two jobs at once. It has to say something about the business, and it has to be readable from across a busy street at speed. Those two jobs pull in different directions more often than people expect, and when they conflict, legibility has to win.

Contrast decides whether the sign works at all

Before any question of mood or brand personality, there is a mechanical question: can someone read this from the far pavement, at a glance, in bright sun?

  • Light text on a dark ground, or dark on light. Those are the two that work. Mid-tone on mid-tone — grey on beige, mid-blue on mid-green — fails at distance even when it looks fine on a screen.
  • Two saturated colours together vibrate. Red on blue, or red on green, produces a shimmering edge that is genuinely tiring to read. Separate them with white or black.
  • Yellow needs a dark partner. Yellow on white is nearly invisible outdoors. Yellow on black or deep blue is one of the most readable combinations there is.
  • Roughly one in twelve men has some red-green colour deficiency. A sign that depends on distinguishing red from green is unreadable to a real share of the people walking past.

A test you can run on your phone

Photograph the artwork, shrink it on screen until it is the size of a postage stamp, and squint. If you cannot tell what it says, neither can a driver at forty metres. This catches more signage problems than any amount of colour theory.

What colours conventionally signal — and the limits of that

Colour association is real, but it is weaker and more local than marketing writing usually claims. Treat these as starting points, not rules.

  • Blue reads as steady and institutional. It is the default for banks, clinics, insurers and logistics for a reason, which is also its weakness — it is crowded.
  • Red reads as urgent and appetising. It works hard for food, retail and clearance, and it is the first colour to fade outdoors if the ink is not UV-rated.
  • Green reads as fresh, agricultural or health-related, and in Kenya it carries mobile-money associations too, which may help or confuse depending on your trade.
  • Black and metallics read as premium, and they are unforgiving — every fabrication flaw shows. Only specify them if the finish quality is there.
  • Yellow and orange read as cheap-and-cheerful or as safety, depending entirely on context and typeface.

The stronger signal is almost always consistency, not the colour itself. A shop whose sign, uniforms, receipt book and delivery vehicle all use the same two colours reads as organised. That impression outperforms any individual colour choice.

Getting the same colour on every surface

This is where most brands quietly come apart. The same file printed on vinyl, on a T-shirt and on a coated business card will not match unless someone manages it.

  • Write your colours down properly. Not “our blue” — the actual values, and a Pantone reference if you have one.
  • Expect substrate shift. Ink on uncoated card sinks in and dulls. The same ink on gloss vinyl sits on top and looks brighter. This is physics, not error.
  • Fabric is the widest gap. Embroidery thread and garment print have their own ranges and will approximate, not match.
  • Approve a physical proof for the first run of anything new. A screen is backlit; your signage is not.

We print signboards, branded apparel and stationery on the same floor, which is the practical reason we can keep a brand consistent across all three.

A short checklist before you approve signage artwork

  • Squint test passed at postage-stamp size.
  • Text and background differ clearly in lightness, not only in hue.
  • No two saturated colours touching without a neutral between them.
  • The design still reads if red and green are indistinguishable.
  • Colours recorded somewhere you can reissue them next year.

Frequently Asked Questions

Dark text on a light ground, or light text on a dark ground — the difference in lightness matters far more than the choice of hue. Black on yellow and white on deep blue are both consistently readable at distance and in bright sun.

Keep the brand colours but adjust how they are used. Put the logo in brand colours and set the legible information — your name, your trade, your phone number — in a high-contrast pair. A sign nobody can read is not on brand either.

Different substrates absorb and reflect ink differently, and different print processes have different colour ranges. Uncoated card dulls; gloss vinyl brightens. Supplying proper colour references and approving a physical proof on each new material keeps the gap small.

Two, plus a neutral, is the safe answer for anything read at distance. More than three competing colours makes the eye work to find the important information, which is the opposite of what a sign is for.