Two seconds

An installation is bought like a piece of furniture: diagonal, resolution, bracket, installation date. But it pays for itself in a currency that appears on no delivery note. Attention is the real currency, and it is scarce, because every person can spend it only once.

Whoever walks past your shop window has a destination in mind, someone beside them, a phone in hand and perhaps rain down their neck. Your screen is one of twenty stimuli within five metres. It does not win because it is bright and large, but because in the fraction it is given it delivers something useful.

Two to three seconds – that is the span we work with as long as people are moving. The figure does not come from a textbook but from standing beside screens and counting. It is uncomfortable, because it rules out almost everything that looks good in a presentation: the corporate film, the running text, three messages on one surface. And it is liberating as soon as you accept it. Whoever has only two seconds must decide – and that decision is the hardest work in any installation.

Eyes do not wander at random. Anyone walking looks slightly down and ahead, to where the floor lies four to six metres away. The head only lifts when something invites it: movement at the edge of the field of vision, a face, a jump in contrast. A display above that line has to fetch the gaze upwards first. That costs one of the two seconds.

This is why mounting height is not a matter of taste. Our rule of thumb: the centre of the surface sits at the eye level of the audience, roughly 1.55 to 1.65 metres above the floor when people are standing; in a waiting area, where they are seated, closer to 1.30 metres. Above doors and counters, screens often hang high only because that was where space was left.

The direction of travel matters too. A surface that only becomes visible once the person is level with it catches nothing but a profile.

And then there is the phone. It takes exactly the seconds that would otherwise have been free: in a queue the head drops after ten or fifteen seconds of idleness, and after that you will hardly get it up again.

In two seconds nobody reads a sentence with a subordinate clause. What gets read is one large line, a number, an arrow, a logo. Our working limit is around seven words per image, and they should fit on one line, not three.

The second limit is type size. It depends not on the screen but on the reading distance: roughly 25 millimetres of letter height per three metres, measured on the glass and not in points in the layout program.

Then there is contrast. Dark type on a light ground wins in daylight, light type on a dark ground in the evening and against reflections. Thin weights and grey tones on photographs are the first to fail in sunlight.

Motion is both things at once: the best attention-getter and the most frequent disturbance. A change at the edge of the field of vision turns the head. Continuous motion, by contrast, has no beginning left for the eye to latch onto, and text that scrolls, rotates or flies in has finished building when the person has already gone. Move the transition, not the message.

There are two fundamentally different kinds of location, and almost every mistake in content planning comes from confusing them.

At a passing place people are moving: shop window, passage, station concourse, entrance area. Here the two-second arithmetic applies in full severity. One image, one statement, a change every six to eight seconds, so the next person still sees something whole. QR codes and telephone numbers are wasted here, because nobody stops to type them in.

At a waiting place seconds turn into minutes: waiting room, checkout area, lift, gym, hotel lobby. Whoever waits does not look once but again and again. Here content may go deeper, and here the QR code pays off, because a hand is free. But here you also need more variety: anyone waiting eight minutes sees a two-minute loop four times.

In the gym you can see how strongly this works: anyone spending forty-five minutes on a cross trainer sees the same surface dozens of times – and notices every repetition.

Almost every weak installation I have seen has the same cause: the screen shows what the client wants to say, and not what the person in front of it is looking for right now.

This happens in almost every project, because the content is created in a meeting room. Sitting there are people proud of the new machine, the anniversary, the mission statement. All of that is true and important. But standing in front of the screen is someone who wants to know where radiology is, what the lunch special is and how much longer it will take.

A simple test helps: write down the question of the person in front of the screen in their own words. «Do I have time for a coffee before my turn.» «Where do I have to go.» If your content does not answer that question, it answers nobody's question.

The second half of the same mistake is quantity. Show everything and you show nothing. Three messages on one surface cancel each other out, because the eye first has to decide where to begin – and it has no time for that. One surface, one thought.

And the third: eternity. A screen that has been running the same images since Easter turns into wallpaper – regular customers notice that faster than any analysis.

«Reach» is the word used to make numbers look big in advertising. For an installation on site it is of little use: a screen has no reach, it has contacts, and every contact has a duration.

Footfall times contact duration gives you the seconds that are genuinely yours. Repeat visits decide how quickly you have to change the content.

You do not need to know these four figures exactly; an honest estimate is enough. They answer what otherwise stays stuck in gut feeling: how large the surface has to be, how long the loop should run – and whether a screen is worth it at this place at all. Two surfaces in the right spot beat six in the wrong one.

What of this can be measured later, and what cannot without monitoring people, is in the chapter on effect.

This book answers a single question in eighteen attempts: how does a screen earn the two seconds it gets? Where technology is necessary, I explain it so that you can judge a quotation.

The first part lays the groundwork:

The second part goes to where the screens stand. Each of these chapters stands on its own; read the one that fits you:

The third part leads back to implementation:

Read it front to back, that is how it is meant – or start with the chapter that is pressing right now. Each one stands on its own and points to where things continue. At the end you will find a glossary and checklists for the site visit.