Not all flicker is visible, but it still affects how we experience light.
In LED lighting, flicker means small, rapid changes in brightness. It may appear as a shimmer or subtle pulse, especially when dimming. Even when invisible, it can cause discomfort, eye strain, or reduced concentration over time.
How we test flicker.
At Karizma Luce, every luminaire undergoes detailed flicker testing before release. Each driver is tested under real conditions — at different dimming levels, colour temperatures, and electrical loads. Our in-house lab uses high-speed sensors and calibrated equipment to ensure stable, comfortable light across the full dimming range.
The table below summarises how these values relate to comfort levels:
| Flicker Level | Percent Flicker | Flicker Index | Recommendation |
| Very low | 0–1% | 0.00–0.01 | Imperceptible; ideal for all applications |
| Low | 1–5% | 0.01–0.05 | Excellent for interiors and hospitality |
| Medium | 5–10% | 0.05–0.10 | Acceptable in indirect or functional zones |
| High | 10%+ | 0.10+ | Avoid in living areas or visual task spaces |
Understanding flicker metrics.
Flicker performance is measured using several international indicators.
Percent flicker shows how much the light output changes within one cycle, while flicker index describes both the strength and shape of that change. Lower values mean smoother, more comfortable light.
Additional European metrics such as PstLM and sVM provide a deeper view of visual comfort.
- PstLM (short-term flicker severity) measures how often flicker is noticeable within ten minutes. A value of 1.0 is the limit of perception; our luminaires remain well below this level.
- sVM (stroboscopic visibility measure) assesses both frequency and waveform. Values below 0.4 indicate comfortable lighting; values above 0.9 may cause discomfort.
Testing tools and conditions.
Our laboratory is equipped with high-speed cameras and waveform analysis systems. These tools capture flicker behaviour under realistic dimming and load conditions. Each LED and driver combination is tested to verify stable performance and compliance with European standards such as IEC TR 61547-1 and EN 61000-3-3.
Requesting a flicker report.
For projects that require documentation, we can provide a detailed flicker report. It includes PstLM, sVM, percent flicker, and flicker index results for the specific configuration used in your project. Simply contact our team to request the report.
Why flicker testing matters.
Flicker-free lighting is not only a technical goal — it’s a comfort standard. Through careful testing, we ensure that every Karizma Luce luminaire delivers smooth, consistent, and visually stable light. The result is lighting that supports focus, comfort, and well-being in every environment.
Led’s delight!
