LED sign board on your phone: how to make a sign people can read

How far away can people read your sign?

Sign makers use a rule called the legibility index: how many feet away a letter can be read per inch of its height. The United States Sign Council Foundation gives 30 feet per inch as the standard figure for signs seen face on, and uses a more cautious 10 feet per inch for signs read at a sharp angle from a moving car. We use the cautious figure here: roughly 1.2 metres of reading distance for every centimetre of letter height.

That rule comes from building signs, so treat it as a rough guide for a phone. But it makes the main point clearly: reading distance depends on letter size, and a phone screen is small. Letters about 2 cm tall would, by that rule, be readable from roughly 2.4 metres. To be read from further away, the letters need to be bigger than a phone screen can usually show. In LED Sign Board, the Fill size in landscape makes capitals roughly 3 to 4 cm tall on a typical phone, which the cautious rule puts at about 4 to 5 metres.

How do you make an LED sign board easy to read?

1. Use as few words as you can. “HAPPY 30TH SAM” beats a full sentence, and a short message can be read at a glance.
2. Pick a bold, simple font. Thin script fonts look lovely close up and blur into lines from a few metres away.
3. Choose strong contrast. Bright letters on a dark background tend to stand out best.
4. Hold it still. A sign that moves with your arm is much harder to read. Rest your elbows or prop the phone up.
5. Test it first. Walk to the far side of the room, or ask a friend to hold it up, and check you can read it from where your audience will be.

Should the text scroll?

Scrolling lets you show a longer message without squeezing it, because only part of it is on screen at once. The trade off is time: people have to keep watching to catch the whole thing. A few tips:

• Scroll only if the message will not fit at a readable size.
• Slow it down for people further away or on the move.
• Repeat short messages so latecomers can catch them.
• Use still text when a single word or name will do.

Is flashing or blinking text safe?

Blinking and pulsing text grabs attention, but flashing light can affect some people. The Epilepsy Society explains that photosensitive epilepsy is when seizures are triggered by flashing lights or contrasting light and dark patterns. It says flash rates between 3 and 30 hertz (flashes per second) are the common triggers, though this varies from person to person, and that flashing or patterned effects can make people with or without epilepsy feel disorientated, uncomfortable or unwell.

A clear warning about LED Sign Board: at its faster speed settings, the app’s blink effect flashes more than 3 times a second, which is inside that common trigger range. For comparison, the Epilepsy Society notes that UK TV rules restrict flashing to three per second or less.

So:

• Use blink and pulse sparingly, keep the blink speed at the default or slower, and never hold a flashing sign right in front of someone’s face.
• Prefer still or gently scrolling text in crowds, at events with children, or anywhere you cannot tell who is watching.
• If you are sensitive to flashing light yourself, do not use flashing effects.

Ideas for your sign

• Airport or station pick ups: a surname in big letters.
• Gigs and festivals: a short message to the band, or a meeting point for friends.
• Birthdays, weddings and proposals: names, a date, or a question.
• Market stalls: “OPEN”, a price, or “CARD OK”.
• Karaoke nights: the next singer’s name.

Questions people ask

Where LED Sign Board helps, and where it does not

LED Sign Board is our Android app that turns your phone into a scrolling LED or neon sign. Type your message and it shows it in LED dots or glowing neon that can scroll, blink, pulse or stay still, in four sizes up to as tall as the screen. It turns the brightness up and keeps the screen on while you show it. It is free with 3 fonts and 3 colourways, works offline and needs no account. A one-time Pro unlock adds your own colours, saved signs, mirror and upside down, 4 more fonts and the Y2K, Karaoke, Wedding, Market Stall and Soft White packs.

What it is good for: quick, bright, readable messages at parties, gigs, pick ups and stalls.

What it will not do: a phone is still a small screen. Even at Fill size it suits people within a few metres, not the back of a hall. For that, a proper printed banner or a real LED display is the better choice. Blink and pulse flash the screen, and at faster speeds blink goes above 3 flashes a second. The app asks you to accept a warning every time Blink would flash that fast, and you can pause the sign at any time. Do not use blink if you or anyone near you is sensitive to flashing light.

Questions or bugs: Email us.

Sources

1. Parallel Mounted Letter Height and Sign Size (2019)United States Sign Council Foundation · usscfoundation.org
2. Photosensitive epilepsyEpilepsy Society · epilepsysociety.org.uk