Aspect ratios, file specs and why they matter
Screen networks publish creative specifications because the players and displays have fixed requirements. A file at the wrong aspect ratio is letterboxed, stretched or cropped; one at the wrong resolution is soft; one in an unsupported format does not play.
These are mechanical constraints and they cause a disproportionate share of avoidable problems.
Why does aspect ratio matter so much?
Because a mismatch has only bad options. A sixteen-by-nine file on a portrait screen either gets bars, a crop that loses part of the message, or a stretch that distorts everything.
A brand with creative in one ratio and a network with screens in another has a production problem rather than a scheduling one, and it should be discovered at brief stage.
What about resolution?
The file should match the display's native resolution. A lower-resolution file is upscaled and soft, which matters most for text — the element the medium depends on.
Over-specifying is harmless in quality terms and produces larger files, which can matter for distribution across a network with variable connectivity.
What are safe margins for?
Screens crop differently and bezels intrude. Keeping critical content inside a safe margin ensures that the message survives a display that renders slightly differently from the design.
That is a real risk in a network of mixed hardware, which many independent-store networks are.
What about duration?
Slot duration is fixed by the loop, and a file longer than the slot is truncated. Designing to the slot rather than to a preferred length is the requirement.
A common error is producing to a familiar digital duration and discovering the loop uses a different one.
What about colour?
Screens vary in calibration and brightness, so colours render differently across an estate. High-contrast, saturated choices survive that variation; subtle ones do not.
Brand colours that depend on precise rendering will vary visibly across a mixed estate, and the design should assume they will.
What should a brand do with the specification?
Give it to the creative team at brief stage and make it a deliverable rather than a check. Most specification failures come from creative produced for another medium and adapted afterwards.
The network's creative specifications are the operative document and should be used directly rather than summarised.
What about mixed hardware?
A network with several screen types may have several specifications. Ask how many, because producing to one and delivering across three is how executions end up cropped in part of the estate.
Frequently asked questions
Can one file work across portrait and landscape?
Not well. Those are different layouts and a brand buying both should produce both, because automatic adaptation produces a compromise that works in neither.
What file format should be used?
Whatever the network specifies, and there is usually little latitude. Delivering in a different format is the most common cause of a rejected file.
Does file size matter?
It can, for distribution across a network with variable connectivity. Very large files take longer to propagate and can miss a start date.
How far in advance should files be delivered?
Earlier than seems necessary, because a rejection plus a re-render plus re-approval takes days. Networks publish deadlines and they exist for this reason.
What about motion versus still?
Both are usually supported and motion has more ways to fail. A still that works is better than a motion piece that renders poorly.
Should text be part of the image or overlaid?
Baked into the file, in almost all cases, so that rendering is predictable. Dynamic overlays depend on the player and add a failure mode.
Does the specification change?
Occasionally, as hardware is refreshed. Check it for each flight rather than reusing a version from last year.
What if my creative is already produced?
Check it against the specification before booking. Discovering a mismatch after the buy is committed is an expensive sequence.
What is the single most common failure?
Wrong aspect ratio, followed by text inside the crop margin. Both are visible in a thirty-second check against the specification.
### How should specification compliance be managed?
By making the network's specification a deliverable in the creative brief and checking against it before delivery rather than relying on the network's rejection. A rejection costs days at exactly the point in the schedule where days are scarce.
Keep a copy of the specification with the campaign file, dated, so that a question months later can be answered against the version that applied.
Where a brand runs across several networks, maintain the union of requirements rather than the intersection, because producing to the most demanding specification works everywhere.
What if the network changes its specification mid-campaign?
It should give notice and the existing files should continue to run. Confirm that, because a mid-flight specification change without notice is a delivery risk.
Should files be archived?
Yes, with the specification they were produced against. Reusing creative a year later against a changed specification is a common source of a rendering problem nobody can explain.
Who should own specification compliance?
The person running the pre-flight checks, using the network's current document. Assuming the creative team checked is how mismatched files reach a network.
Does a rejected file delay a flight?
Frequently, because re-rendering and re-approval both take time. That is the practical argument for checking before delivery rather than relying on rejection. Industry standards work is discussed by bodies such as the IAB.
Considering NRS Digital Media? Start at nrsdigitalmedia.com, read the media deck, or contact the team.