Online daylight reflectance calculator

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Online total daylight reflectance calculator

Total daylight reflectance
The fraction of daylight reflected by a surface, including both diffuse and specular components
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©OTM Solutions Pte Ltd, V1.0.0, 13/06/2021

How to use this calculator?

Simply select a color with the color picking tool or input the color value (RGB, HSL or HEX, at the bottom of the color picking tool). The corresponding total daylight reflectance is displayed.

What is total daylight reflectance?

Total daylight reflectance is a building façade and roof material property required in Singapore (What is daylight reflectance?).

Total daylight reflectance is equivalent to visible light reflectance, luminous reflectance and light reflectance value.

How does this calculator work?

In screen display, the sRGB color space is commonly used. For example, on our website, all hyperlinked texts are displayed as RGB (119, 204, 109) or HEX (#77CC6D) color.

This calculator calculates the luminance (the Y component in the CIE XYZ color space) from the sRGB color space, following this Wikipedia article.

How accurate is this calculator?

The conversion from the sRGB color space to the CIE XYS color space is a theoretical conversion and is free from errors.

However, for a physical sample, usually we do not know its color value in the sRGB color space. We need to manually estimate an sRGB color. Some errors arise in this estimation (e.g. human vision error, screen color display error, illumination error, etc.).

Nevertheless, this calculator is still a useful tool to relate screen displayed colors to physical colors.

If accurate daylight reflectance measurement is needed, please considered our daylight reflectance measurement service.

Can this calculator calculate diffuse and specular daylight reflectances?

No. The diffuse and specular daylight reflecances are dependent on the surface finishing and there is no theoretical models for such calculations.

Please consider our daylight reflectance measurement service if such information is needed.

How to convert a RAL color to an sRGB color?

RAL colors are physical colors and they cannot be converted to sRGB colors theoretically. A RAL color can only be matched to an sRGB color manually (with certain error).

There are a few websites listing the approximated sRGB color values of RAL colors:

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Comments or feedback?

Please feel free to leave your comments or feedback to this online calculator in the “Leave a Reply” section at the bottom of this page. We will improve this online calculator regularly.

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