Online luminance contrast calculator

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Online luminance contrast calculator

Color 1 luminous reflectance
The fraction of visible light reflected by a surface; indicating the brightness of a surface
 = 
Color 2 luminous reflectance
The fraction of visible light reflected by a surface; indicating the brightness of a surface
 = 
Luminance contrast
The contrast of brightness between colors 1 and 2
 = 
©OTM Solutions Pte Ltd, V1.0.0, 19/06/2021

How to use this calculator?

Luminance contrast is always in terms of two colors. Simply select two colors with the color picking tool or input the color value (RGB, HSL or HEX, at the bottom of the color picking tool) of each color. The corresponding results of luminous reflectance and luminance contrast are displayed.

What is luminance contrast?

Please read this blog post for more information: Luminance contrast: calculation method and a few examples.

Luminance contrast indicates the contrast in brightness and it is different from color contrast. If you play with this calculator, you may notice that some color pairs with distinct colors are with small luminance contrast.

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, equivalent to the luminous reflectance) from the sRGB color space, following this Wikipedia article. The luminance contrast is then calculated from the luminance of the two colors.

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 luminance contrast measurement is needed, please considered our luminance contrast measurement service.

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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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