What Is the Influence of Light on Color in the Work of a Color Assessor?

You probably know this: in daylight, something looks completely different than under a lamp. This phenomenon is called metamerism and is an important concept for anyone who works professionally with color. You can assess the color by holding the physical color sample next to the colored surface — but then you must take the lighting conditions into account.

Light Determines How Color Appears

Daylight in the morning is different from around noon or in the evening. The season and location on earth also affect the spectral composition of light. This knowledge is essential for color specialists and specifiers — architects, designers, product managers — because they always deal with their customers' color perception.

Light affects not only how a color appears, but also whether two colors match. Two materials that look identical under daylight can clearly differ under fluorescent or LED lighting. This is metamerism — and it is one of the most common causes of color complaints in the chain.

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Standardized Light

To be able to reliably assess color, light booths have been developed. A light booth provides:

• A neutral environment (mid-gray) without color contamination from reflections
• Multiple standardized light sources to detect metamerism
• Reproducible conditions so assessment is repeatable

The light sources in a light booth are standardized by the CIE (Commission Internationale de l'Éclairage). The most commonly used standards:

| Light Source | Color Temperature | Application | | ------------ | ----------------- | ------------------------------------------------- | | D65 | 6,500 K | Daylight — primary assessment standard | | D50 | 5,000 K | Graphic industry, printing | | A | 2,856 K | Incandescent lamp — warm artificial light | | TL84 | 4,000 K | European retail lighting | | CWF | 4,150 K | American retail lighting (Cool White Fluorescent) | | LED | Variable | Modern retail and office lighting |

By assessing a color sample successively under these light sources, it becomes visible whether metamerism is present.

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Dependent on the Market and End User

As a professional, you create an environment in which you can assess color. That environment is neutral and can be a light booth, but also an assessment room with daylight lamps and a diffuser.

The choice of light source depends on the market and the environment in which the end user will see the product:

• Wallpaper → assess under daylight and the light source of the application room
• Clothing → assess under daylight and LED or TL84 (retail lighting)
• Food packaging → assess under D65 and supermarket lighting
• Car paint → assess under daylight and multi-angle for metallics

The right light source choice prevents a color that is approved in the lab from deviating for the end user.

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The Chain

For color assessors, it is important that the same light standard is used throughout the entire chain.

Take the printing ink industry: there, color is assessed on D50. When the ink producer assesses on D65 and the printer on D50, they literally do not speak the same language — even though they use the same color values.

Therefore, ensure alignment of light conditions throughout the entire chain:

• Raw material producer → color producer → processor → end product
• Everywhere the same light source, the same geometry, the same assessment conditions

Only when the entire chain assesses under the same conditions is color communication reliable.

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Related products:

• VeriVide Light Booths — standardized lighting for color assessment

Related services:

• Training & Testing — validate perception ability
• Instrumentation & Advice — light source selection and configuration