Daylight reflectance, color and gloss

Color and gloss are commonly used quality check quantities by material suppliers and construction companies, whereas daylight reflectance are relatively new to the industry. This article aims to explain the relationship between the three quantities.

Daylight reflectance and color

The total and diffuse daylight reflectance is directly related to color. Materials with light color are with high total or diffuse daylight reflectance; materials with dark color are with low total or diffuse daylight reflectance. Our eyes cannot quantify daylight reflectance, but they can assess daylight reflectance qualitatively.

Most color instruments with integrating sphere geometry can measure color in the SCI (specular component included) mode or the SCE (specular component excluded) mode. Color measured in the SCI mode is equivalent to the total daylight reflectance; color measured in the SCE mode is equivalent to the diffuse daylight reflectance.

The closest color scale is Yxy scale. Of course, due to various technical constraints, color measurement instruments cannot accurately determine daylight reflectance, but the results are sufficient for internal use.

Daylight reflectance and gloss

The specular daylight reflectance is directly related to gloss. Materials with high gloss are with high specular daylight reflectance; materials with low gloss are with low specular daylight reflectance. Our eye can qualitatively assess if a surface is with high gloss or with low gloss.

Gloss meters can measure material gloss level. However, the relationship between gloss meter readings and specular daylight reflectance is qualitative. It is not possible to quantitatively coorelate them.

Notes to applications

For projects where low specular daylight reflectance is required, materials with low gloss level are preferred.

For projects where low total daylight reflectance is required, materials with dark color are preferred.

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