As suggested by the title of ASTM E903:
Standard test method for solar absorptance, reflectance, and transmittance of materials using integrating spheres
ASTM E903 is for the testing of solar absorptance, reflectance, and transmittance, but not daylight reflectance directly. The procedures of spectral reflectance measurement with integrating spheres are described in ASTM E903 in detail, but it is still insufficient to get the daylight reflectance results with ASTM E903 only.
Therefore, at OTM, ASTM E903 is supplemented with other test methods in daylight reflectance testing:
- For general materials: ASTM E971 and CIE 130
- For glass materials: NFRC 300
Please refer to our daylight reflectance page for more information.