Related services Daylight reflectance
It is possible to measure the daylight reflectance of a surface using a portable colour meter. For best results, a portable colour meter equipped with an integrating sphere is recommended.
The preferred measurement settings are:
- Illuminant: D65
- Observer: 10° standard observer
- Colour space: Yxy
Many colour meters provide two measurement modes:
- SCI (Specular Component Included): The Y value obtained in this mode is equivalent to the total daylight reflectance.
- SCE (Specular Component Excluded): The Y value obtained in this mode is equivalent to the diffuse daylight reflectance.
The difference between the SCI and SCE Y values is equivalent to the specular daylight reflectance.
Q: Can the results measured with this method be used for BCA submission?
A: No. The Building and Construction Authority (BCA) requires testing in accordance with ASTM E903. Portable colour meters do not meet this requirement and therefore cannot be used for BCA submissions.
Q: How accurate are the results?
A: Accuracy depends largely on the performance of the instrument.
As a general guideline:
- For colour meters based on the spectrophotometric method, the total daylight reflectance results are reasonably accurate, especially for neutral colours.
- The diffuse and specular daylight reflectance results are typically less accurate, since the integrating spheres in most portable colour meters are relatively small.
Despite these limitations, the measurements remain useful for preliminary assessments and internal evaluations.
Q: What if my colour meter measures only L*ab?
Some online tools are available to convert L*ab results into Yxy colour values. One example is: Convert Lab to Yxy