Planning and specifying an LED display

11.1 Start with the communication objective

Write the objective in operational terms. Examples include:

• display 1080p programme video to an audience seated 4 to 20 metres away;

• present spreadsheet text legibly from every meeting-room seat;

• remain readable in direct afternoon sun;

• photograph cleanly on specified broadcast cameras;

• provide a defined availability level for critical information;

• change campaigns remotely across several sites.

A precise objective prevents the specification from becoming a list of fashionable features.

11.2 Define the audience and viewing geometry

Record minimum, typical and maximum viewing distances, horizontal and vertical sightlines, seated and standing positions, and any obstructions. A floor plan and section are more useful than a single viewing-distance number.

Consider people at the edges of the audience, not only the central design position. A wide nominal viewing angle does not guarantee consistent colour or brightness at every seat.

11.3 Survey the ambient light

Ambient light changes throughout the day and year. Measure or model the brightest relevant conditions, including direct sun, skylights, shopfront glazing, stage lighting and reflected light from pale surfaces.

For indoor projects, black-level performance under room light can be more important than peak luminance. For outdoor projects, the control range matters: the screen must be bright enough in daylight and capable of comfortable night-time operation.

11.4 Define content before finalising the canvas

Ask what will be shown: text, live video, dashboards, advertising, cinematic content, fine diagrams or abstract art. Obtain representative files and test them on a sample at the intended distance.

The content plan should identify:

• native pixel dimensions and aspect ratio;

• smallest intended text and line weight;

• frame rates and HDR or SDR format;

• safe areas for irregular canvases;

• content ownership and approval;

• update frequency and scheduling;

• fallback content when a source is unavailable.

11.5 Select size and pitch together

Size, pitch and resolution are connected. Begin with the physical area needed for visibility and impact, then determine the pixel density required for content and distance. Avoid selecting an extremely fine pitch for a display so small that the audience cannot read the content, or a large screen whose coarse resolution makes detailed material unusable.

A sample comparison should use the same content, similar luminance and representative room lighting. Manufacturer demonstration reels often use large, high-contrast imagery that hides weaknesses in text and low greys.

11.6 Establish image-quality requirements

A balanced specification may include:

• target luminance range, not only maximum;

• acceptable colour and luminance uniformity;

• colour-space and white-point targets;

• camera frame rates and shutter conditions;

• refresh and low-grey behaviour;

• black-level performance under ambient light;

• viewing-angle acceptance criteria;

• latency limit where relevant;

• sample or factory-acceptance tests.

Where a metric lacks a universally comparable method, describe the visual outcome and test method rather than quoting an arbitrary number.

11.7 Plan structure, access and interfaces

The supporting structure must address static load, dynamic load, wind where relevant, deflection, fixing points, tolerances and access. Temporary systems require competent rigging and event-specific controls. Fixed systems may fall within the duties of designers, clients and contractors under the Construction (Design and Management) Regulations 2015.

Coordinate screen depth, ventilation, doors, hatches, edge finishes, speaker positions, sprinklers, detectors, lighting, cable routes and architectural joints. Late coordination can make an otherwise suitable product difficult to operate or maintain.

11.8 Plan electrical and data infrastructure

Electrical design should consider maximum demand, diversity, distribution, protective devices, isolation, earthing, voltage drop, harmonic effects where relevant and any need for uninterruptible power. The design must be undertaken and verified by competent professionals under current requirements.

Data planning should identify source locations, cable types and distances, network ownership, fibre routes, redundancy, equipment rooms and cybersecurity boundaries. Separate pathways can be necessary when resilience is important.

11.9 Define service access and working conditions

Access is a design requirement. Ask which assemblies can be reached from the front or rear, what clearances are needed, whether lifting aids are required and how work is isolated from occupants or the public.

A wall that can technically be serviced from the front may still be unsuitable if the display is above stairs, behind furniture or in a continuously occupied control room. Plan access around real tasks and safe working methods without prescribing those methods in the public specification.

11.10 Define supportability and parts availability

Product generations can differ in LED batch, optical surface, firmware, driver design and correction data. Procurement should establish the expected period of authorised support and compatible-parts availability, together with the organisation responsible for that support.

Specific storage, inspection, matching, configuration and replacement methods are outside the scope of this guide and belong within the relevant professional support arrangement.

11.11 Procurement evidence

Useful evidence includes product data sheets, test reports, environmental certifications, sample panels, factory or site demonstrations, reference projects with similar duty, warranty terms and support arrangements.

A tender response should separate confirmed compliance from exceptions and options. Phrases such as "or equivalent" need measurable criteria, otherwise proposals cannot be compared fairly.

11.12 Factory and site acceptance

Acceptance testing should reflect the application. It may include physical dimensions, pixel map, inputs, redundancy, representative content, colour and luminance uniformity, camera tests, environmental controls, monitoring, safe isolation and documentation.

Acceptance documentation should state the agreed visual and system-performance baseline at commissioning. This is a contractual handover record rather than a diagnostic or maintenance procedure.

11.13 Total cost of ownership

Whole-life cost may include:

• display, processing, structure and installation;

• electrical and data infrastructure;

• content creation and management;

• energy;

• planned inspection and cleaning by competent providers;

• spares, warranty and support;

• access equipment and downtime;

• refurbishment, relocation and end-of-life treatment.

Price per square metre is therefore a weak decision metric when used alone.

11.14 Questions to ask a prospective provider