Flashing and safety — Wildlights

The three settings

You pick one when you build a show. It is the ceiling for the entire show, and the show is rewritten to fit it rather than being allowed to exceed it.

Setting	What it allows	Where it fits
Gentle	At most one flash a second, anywhere in the show.	Weddings, dinners, anywhere with guests you know are sensitive, and any room where you would rather not think about it.
Standard	At most three flashes a second — the usual public guideline.	The default, and the right answer for most events.
High	Short strobe-like bursts above three a second, only at the biggest moments, bounded in length and spaced apart.	Concerts and club-like rooms where a strobe is expected and announced.

On top of the setting, each event has its own hard limits — whether strobe is allowed at all, the fastest rate, the longest burst, and the minimum gap between bursts. An event that forbids strobe gets no strobe even on the highest setting at the highest energy.

Why it is measured, not assumed

A light show is made of layers. A pulse underneath, a rhythm on top of it, a flash landing next to both. Each part can be within the limit while the thing a phone actually displays is not — this is the way a well-intentioned limit usually fails.

So Wildlights does not check the parts. It runs the finished show through the same engine the phones run, samples what the screen would be showing, and counts flashes in every sliding one-second window across the whole show, including across the joins between cues. If any window is over the limit, the show is changed and measured again, until it passes.

Two details worth stating, because they are the ones usually missed:

Brightness is judged the way an eye in a dark room judges it. A saturated blue phone flashing on and off is a flash, even though its luminance never approaches white. Using luminance alone would wave most of a colourful show through.
Saturated red is counted separately. A phone alternating between red and blue can hold its brightness steady and still be flashing red, which is its own recognised risk. That is counted on its own terms.

What gets changed when a show is over the limit

The repair tries to keep the show recognisable. It softens the texture first — the fine detail on top of a look, then the contrast within the movement — and only removes an actual moment of emphasis when nothing else is enough. A drop stays a drop; what goes is the stippling around it.

The guidelines this follows

The three-flashes-a-second ceiling is the common thread in the public guidance on photosensitivity — it appears in the Web Content Accessibility Guidelines (2.3.1 and 2.3.2), in broadcast guidance such as Ofcom's and ITU-R BT.1702, and in the Harding test used for television. The separate treatment of saturated red comes from the same place.

Wildlights follows the shape of that guidance and measures itself against it. It is not certified by anyone, and this page is not medical advice. If you are running an event where this genuinely matters, use Gentle.

What to tell people

Whichever setting you choose, tell the room. A line in the programme, on the join screen, or from the stage — the same way a venue warns about strobes — lets anyone who needs to look away, sit out, or keep their phone in a pocket. Nobody who joins is ever obliged to hold their phone up.

Two practical things worth knowing: a phone that stays in a pocket is simply a phone that is not in the show, and anyone can close the page at any time with no effect on anyone else.

The stop button

Whoever is running the show can take every phone in the room to black instantly, at any point, without stopping the music or unwinding anything. If something is not right, that is one press away.