LED wall

It is assembled from panels, so the size follows the room rather than a catalogue. More important than the diagonal is pixel pitch, the distance between points. The closer people stand, the finer the pitch you need, otherwise they see the grid. A conference where the front row sits three metres away needs a finer panel than a trade fair stage with the audience ten metres back. Build takes half a day to a day and needs its own power supply.

Why it earns its cost: projection in a lit room washes out and the organiser has to dim the lights, which sends the audience to sleep. An LED wall works in daylight, so you can present with the lights on. On a trade fair stand the difference is that the screen is visible from the aisle. Hire costs several times more than a projector, so the decision turns on whether the screen is scenery or the main carrier of content.

What to prepare: content in the right aspect ratio, which is only known once the wall is specified, because its size depends on the number of modules. So do not build the graphics before you know the exact resolution. Text has to be large, it is read from ten metres. And agree who drives the content during the programme, usually a vision operator rather than the speaker.

When it is unnecessary: in a small meeting room for thirty people, where a television is enough. And at an event that only shows a logo and session titles, which a projector handles for a tenth of the price. Note too that an LED wall behind a speaker complicates filming, because the camera samples it at a different rate and bands can crawl through the shot, so shutter speed and sometimes the wall's refresh rate have to be set.

With an LED wall we settle the content before the technology. Once it is clear what will be shown, the size and pixel pitch choose themselves. Try it today: look at photos from your last event and notice whether anything on the screen helped the talk, or whether it was just a logo.