Start with the collection

Museum lighting begins with the collection: its sensitivity, display schedule and conservation policy. A suitable specification combines object-level illuminance and exposure management with appropriate colour quality, optical control, dimming, thermal management and documented product performance. No single CRI value or manufacturer name establishes conservation suitability.

Start with a conservator-approved display brief. Then evaluate the exact luminaire, LED, driver, optic and control combination against that brief, using test data and a representative mock-up before procurement.

Illuminance and cumulative exposure

Set illuminance for each object, considering pigments, dyes, coatings, repairs and mixed materials. Traditional planning references include approximately 50 lx for sensitive collections, around 150 lx for many painted or organic objects, and around 300 lx for relatively insensitive inorganic objects. These are starting points, not universal safe limits. A fragile component can determine the limit for an otherwise robust object. Display cases require the same object-based assessment.

Agree the final illuminance, display duration and exposure allowance with the conservator or lender. Include daylight and operating hours, then measure at the object during commissioning. Visible light can cause cumulative fading even when UV is very low.

For a constant 50 lx over 8 hours per day and 250 days, exposure is 100,000 lx·h. This calculation does not establish an acceptable annual budget; it shows how a proposed display schedule consumes the budget approved for that object. For variable light levels, add the exposure from each time interval.

References: Canadian Conservation Institute: Light, ultraviolet and infrared · Canadian Conservation Institute: Caring for paintings

UV, infrared and thermal management

Request source-specific spectral information and assess UV output where collection sensitivity requires it. Low UV and low forward infrared emission do not eliminate visible-light damage or heat from the luminaire. For cases, assess the complete installation, including ventilation, surface temperatures and the object microclimate. Locate drivers outside cases where practicable and verify temperatures after installation.

Colour rendering: CRI and TM-30

For projects prioritising faithful colour appearance, CRI Ra ≥90 can be used as an initial procurement criterion, with Ra ≥95 considered for more demanding displays. These are proposed design criteria, not universal conservation requirements. Request R9 and a full TM-30 report, including the colour vector graphic, rather than relying on Ra alone.

TM-30 Rf describes average colour fidelity; Rg describes average gamut area. A proposed brief might use Rf ≥90 and Rg 95–105, but these values require curatorial approval and do not guarantee accuracy for every hue. Evaluate representative artworks or approved surrogates in a mock-up. Agree CCT, Duv and colour consistency together; ≤3 SDCM can be a project target, with tighter matching considered for adjacent luminaires. Confirm replacement and ageing tolerances separately.

References: IES: Position on TM-30 · IES: Colour rendition metrics

Flicker and camera compatibility

Require measured temporal light modulation data for the complete luminaire and driver combination. Report PstLM, SVM, modulation frequency and the test conditions, including representative dimming levels. Where appropriate, the project may adopt PstLM ≤1.0 and SVM ≤0.4 as initial acceptance criteria; these are not a guarantee of camera compatibility. For filming, test the intended frame rates and shutter settings at the required dimming levels.

References: US Department of Energy: Flicker research · US Department of Energy: Temporal light modulation review

Dimming and exposure controls

Specify the control protocol, minimum stable measured light output, dimming curve, repeatability and switch-on behaviour. Verify smooth transitions, colour stability and temporal light modulation with the selected driver, controller and load. A claimed 1% minimum must be demonstrated for the supplied configuration. Use occupancy controls or timed scenes where suitable to reduce unnecessary exposure.

Picture lighting and wallwashing geometry

For picture accent lighting, an aiming angle around 30° from vertical is a useful starting point. Adjust it to control frame shadows, reflections and viewer shadows. This is distinct from grazing, which places light close to a surface to reveal texture.

For wallwashing, begin with a wall offset around one-third of the mounting height, then determine spacing using the selected optic's photometry. Define the evaluation area, measurement grid and uniformity metric in the project brief. Validate the layout with calculations and a mock-up, then measure the installed result.

References: ERCO: Picture lighting and wallwashing

For adjustable picture accent lighting, explore the HS-CXT 48V Zoomable Magnetic Track Spotlight as a product option for evaluation. Its adjustable beam can help accommodate different artwork sizes; confirm the selected model’s beam range, track compatibility and measured performance against the project brief.

Glare, photometry and commissioning

Assess direct glare and reflected glare from actual visitor positions, including reflections in glazing and polished surfaces. Specify shielding and accessories where needed. Where UGR is applicable, use a calculated installation assessment; a product-level claim alone does not describe every gallery layout. Request IES or LDT photometry and project calculations, then confirm artwork illuminance, reflections and aiming on site.

Market compliance and documentation

For each destination market, request the applicable conformity documentation for the exact supplied model and configuration. For EU supply, review the EU Declaration of Conformity and supporting technical evidence for the legislation that applies. For UK supply, check the current requirements for Great Britain or Northern Ireland as relevant. For North American projects, verify the required safety listing and exact model in the relevant certification directory. Treat any rebate or efficiency qualification separately from safety compliance and conservation performance.

References: European Commission: The Blue Guide · UK Government: CE and UKCA market guidance

Comparing lighting suppliers

Compare suppliers against the same project brief and exact product configurations. ERCO, Zumtobel, iGuzzini, Lumenpulse and OEM/ODM suppliers can be included in a project shortlist, subject to regional availability and the required documentation. Evaluate optics, measured colour performance, dimming, technical support, warranty and replacement availability rather than assigning performance by brand category.

Customisation scope, private-label availability, minimum order quantity, price and lead time must be confirmed in a current written quotation. Some established lighting brands also offer project-specific adaptations. No equivalence between suppliers is implied without comparable test evidence and project validation.

References: ERCO: Customisation options for showcase lighting

Evaluating a VOC Lighting OEM/ODM proposal

For an OEM/ODM enquiry, ask VOC Lighting to confirm which configurations can satisfy the project brief. Request model-specific spectral and photometric reports, colour consistency information, dimming test results, applicable conformity documents and a sample for assessment. Confirm branding options, minimum order quantity, production lead time, warranty and replacement support in writing. Final suitability depends on the supplied configuration and project acceptance testing.

For projects considering a mains-voltage track layout, browse VOC Lighting’s 220V Track Lighting System to compare track families, spotlights and connection components. Confirm the selected rail, adapter, driver and control configuration together before specifying the system.

Selection workflow and frequently asked questions

1. Obtain the conservation and curatorial brief.
2. Translate it into measurable product and installation requirements.
3. Shortlist suppliers with evidence for the proposed configurations.
4. Evaluate samples, calculations and a representative mock-up.
5. Confirm commercial terms and acceptance criteria before ordering.
6. Commission the installation and retain an exposure-management record.

Does high CRI make a luminaire suitable for conservation?

No. Colour rendering describes visual appearance. Conservation suitability also requires assessment of the object, spectrum, exposure schedule and thermal conditions.

How should a museum evaluate an OEM lighting proposal?

Request evidence for the exact configuration, compare it against the project brief, and verify samples and controls before approving production. Include warranty and future replacement support in the evaluation.

What should a museum lighting enquiry include?

Provide room dimensions, artwork positions, collection restrictions, display hours, target appearance, controls, destination market, quantities and programme. Ask the supplier to identify any requirements that cannot be met or verified.

Successful exhibition lighting depends on a documented brief, verified products and careful commissioning. Keep exposure management and maintenance active throughout the display period.

Planning a museum or gallery lighting project? Send VOC Lighting your layout, collection requirements and procurement brief to request a configuration-specific proposal and supporting documentation.