Digital screen advertising

A digital screen sells you time rather than space. Your file joins a loop of advertisements playing over and over on the same panel, and what you buy is a slot inside that loop for a run of days or weeks. The panels range from digital 6-sheets in supermarket lobbies and bus shelters to atrium towers beside an escalator run and large-format LED over an arterial road.

That one difference changes everything downstream. There is nothing to print, files can be live within 48 hours, creative can be swapped mid-run, and the same screen can carry a different message at breakfast and at closing time. It also means you share the panel — so the first question about any screen is who else is in the loop.

Digital 6-sheets, usually called D6s, are the workhorse: 1.8 metres of portrait glass at pavement level or just inside a store, running a native 1080 × 1920 file. Mall and atrium towers are larger, sited against the flow of footfall, and priced on dwell rather than volume. Large-format roadside LED is the digital equivalent of a 48- or 96-sheet, built to a bespoke resolution rather than a standard one. Then there are venue networks — gyms, offices, forecourts, waiting rooms — where the screen is small but the audience is standing still.

Two specifications actually matter when you compare screens. Pixel pitch, the distance between LEDs, sets how close you can stand before the image breaks up: fine pitch indoors, coarse pitch on a screen read from eighty metres. And whether the screen accepts motion — most do, a few networks take static images only, and almost all run silent, so a video that relies on a voiceover is a video that plays to nobody.

A loop is the full cycle of advertisements on a screen. If the loop is 60 seconds and slots are 10 seconds, the screen carries six advertisers and your slot plays once a minute — sixty times an hour, and one sixth of every hour the screen is on. That fraction is your share of voice, and it decides value: a 10-second slot in a 60-second loop is worth twice the same slot in a 120-second loop on the same screen for the same money.

Screens are sold by the week per screen, or as a package across an operator's estate, where the per-screen rate falls sharply above roughly twenty screens. Some inventory is also sold programmatically by the impression on a CPM, which lets you buy dayparts, weather triggers or specific hours instead of whole weeks. However you buy, get the loop length in writing — it is the variable operators are least likely to volunteer.

The audience figure on a screen listing is modelled the way a billboard's is: footfall or traffic past the site, discounted for who could actually see the panel, then divided by the share of the loop you hold. Dwell time does most of the work indoors. A screen facing a queue or an escalator run is read for twenty seconds or more; a screen in a corridor gets three, and no amount of footfall fixes that.

The number to insist on is the proof-of-play report — a log of every time your file played, on which screen and at what time. It is the only part of an outdoor campaign that is counted rather than estimated. Ask whether it is included before you book, and ask what the operator does about downtime: screens go dark for maintenance, and a good contract makes those plays up rather than absorbing them.

Supply MP4 with H.264 video, or JPG and PNG for static, at the screen's exact pixel dimensions — a file at the wrong aspect ratio is rejected rather than scaled. Strip the audio track. Build to the exact slot length with a hard cut at each end, because many networks trim rather than fade and a fade to black reads as a broken screen. Keep the message to a few seconds of reading: ten seconds is two beats, not a story.

Twenty-four to forty-eight hours before the first play is the normal deadline, which makes digital the only format here that can respond to something that happened this week. Use it. Several creatives across one run costs nothing extra on most networks, so a campaign can open with a launch message, switch to a price at the weekend and close on a deadline — the same budget doing three jobs.

Speed and flexibility are the real advantages: live in two days, changed at will, scheduled by hour and day, and reported with a play log. Indoors, next to the point of sale, screens are the closest outdoor gets to intercepting a decision. The absence of print also makes short runs viable — a single week on a screen is a sensible buy in a way that a week on paper usually is not.

The losses are attention and exclusivity. You hold a fraction of the panel, the message is gone in ten seconds with nothing left behind, and a screen shared with five other advertisers is one the eye learns to skip. Bright ambient light washes out cheaper panels, some councils enforce curfews that switch screens off overnight, and an impressions figure generously counts everyone who walked past, including everyone facing the other way.

Ask four things about the inventory: the loop length and how many advertisers are in it, the operating hours including any curfew, the native resolution and accepted file types, and whether a proof-of-play report is included. Those four decide what you are actually buying, and none of them show up in a price.

Then check the commercial detail. Can creative change mid-run, and does it cost anything? Who approves the artwork and how long do they take — shopping centres and station operators usually hold a veto and their own turnaround. Is there any category exclusivity, or could a competitor sit in the next slot? And what is the remedy if the screen is dark for part of your week?