What To Prioritize When Lighting A Musuem

Light Spectrum, Color Rendering and Consistency over Time:
The light spectrum emitted by museum lights can significantly impact the visibility and color accuracy of paintings. Opt for lights that provide a balanced spectrum, closely resembling natural daylight. High Color Rendering Index (CRI) lights, preferably above 90, ensure that colors appear true to the original artwork.
According to the Guidelines for Selecting Solid-State Lighting for Museums, some LEDs can self-regulate temperature “to avoid or reduce the risk of sustained higher temperature operations that will tend to reduce lifespan.” This means that it’s possible for your LED lux readings to vary during the day, although the authors claim small fluctuations are unlikely to be large enough to cause a problem or be noticed by visitors.

Illuminance Levels
Maintaining appropriate illuminance levels is crucial for both the visibility of the paintings and their preservation. You should aim for a balance between sufficient light intensity for viewing and minimizing the potential damage caused by excessive exposure. You can use this reference document on light levels for storage and exhibition by the Conservation Center for Art and Historic Artifacts

Beam angle and directionality
The beam angle and direction of museum lights play a significant role in the overall lighting effect. When installing lights for the first time, it is advisable to get adjustable fixtures that allow precise control over the beam angle
Since your painting is likely to be protected by glazing or display cases, make sure you test your lighting angles to avoid annoying reflections. Don’t forget that directional lighting can also accentuate texture and brushwork, enhancing the viewer’s experience.

Flicker and dimming capabilities
Lights with dimming capabilities will enable you to adjust the light levels for different exhibitions or conservation purposes, but LEDs might have issues with their dimmers that cause them to flicker, which is not ideal. You can get around flickering issues by using different types of screens to reduce intensity – just make sure your screen is not interfering with your color temperatures.

Heat output
Excessive heat from museum lighting can accelerate the deterioration of paintings, particularly delicate materials such as paint layers. It can also cause differential expansion between the layers and the substrate, leading to cracking and loss of surface. Opt for lights that produce minimal heat emission, such as LEDs. This helps maintain a stable environment around the artwork, reducing the risk of damage. Once again, don’t trust the labels on your lamps blindly. Use a data logger or a manual spot reader to make sure the temperature inside your cases or around your objects remains acceptable