A sample should answer a specific question: will this design meet the visual, mechanical and electrical requirements of the finished fixture? Looking at the light while it rests on a desk is not enough. The sample should be reviewed in the same orientation, viewing angle and approximate ambient light as the installation.
Before the sample is made
Agree the drawing and the reference conditions first. Confirm whether the supplier is making a material sample, an appearance sample, a functional prototype or a production-equivalent sample. Each has a different purpose and level of tooling or assembly.
- Final drawing with dimensions, tolerances and material notes
- Target application and position in the fixture
- Viewing distance and normal viewing direction
- Reference colour, brightness and surface finish
- Graphic artwork or diffuser sample where relevant
- Voltage, driver, connector and control requirements
- Known installation constraints and service access
1. Check dimensions and fit
- Critical outer dimensions and thickness
- Shape, cut-outs, holes and edge finish
- Fit in the intended cavity or frame
- Mounting points and clearance for wiring
- Corner treatment and visible seams
- Flatness or warp where the part must sit flush
Use the same measuring method and units as the production drawing. Record where the part is intentionally loose or tight and confirm which dimensions are critical for assembly.
2. Review light uniformity
- Bright bands or darker areas near the edges
- Visible extraction dots or LED hotspots
- Centre-to-edge variation
- Patterns caused by the light guide or diffuser
- Uniformity at the normal viewing angle
- Changes caused by the final printed graphic
A photograph can exaggerate or hide variation depending on camera settings. Judge the sample visually at the normal distance, then use measurements or agreed comparison images where the project needs a documented acceptance criterion.
3. Confirm colour and brightness
Compare the sample under the lighting conditions expected in the project. Look for batch-to-batch colour differences, pink or green tint, dim areas and changes when dimmed. Confirm the agreed colour temperature and CRI, then review the illuminated appearance of the actual product or graphic rather than an isolated white panel.
4. Inspect electrical and thermal details
- Voltage and polarity marked correctly
- Connector type, retention and cable length
- Solder joints, insulation and strain relief
- Driver compatibility and dimming behaviour
- Temperature after a realistic operating period
- Access for installation and future service
5. Test handling and assembly
Install the sample at least once in a representative fixture. Check whether the cables can be routed, whether the part can be held without damaging the surface and whether the installer can complete the connection in the available space. For a rollout, this can reveal problems that are invisible when the sample is viewed on a table.
6. Agree the production standard
Once the sample is accepted, keep an approval record that travels with the project. The record should identify the drawing revision, material, LED configuration, diffuser, graphic, connector, serial or sample number, and the tests performed. This helps prevent a later batch from drifting to a different appearance or assembly detail.
The light source, light guide, diffuser, printed graphic, mounting and power supply all affect the final result. Approve them together rather than treating each component as an unrelated purchase.
Questions to record for every approval
- Drawing revision and sample reference number
- Date, reviewer and intended installation
- Measured dimensions and fit result
- Uniformity, colour and brightness observations
- Electrical checks and operating conditions
- Required changes and whether a new sample is needed
- Production release date and approved quantity
Start with our custom LED light guide guide or review custom LED light guide plates. Send the drawing, target appearance and sample requirements through the project quote form.