Luminance and Brightness: What is the Difference?

Posted May 22, 2019 by Kevin Aamodt

A calibrated display is not just for photographers. If you browse inspiration photos online, send color samples back and forth via e-mail, or transfer color files between suppliers and customers, you need to calibrate and profile your display to trust the colors you see on-screen.


luminance vs brightness blog monitor calibration


When talking about monitor calibration, many people interchange “luminance” and “brightness,” but they are not the same. 


What is luminance?

Luminance is a measurement of the intensity of light emitted from a surface. It is objectively measured using “Candela per Square Meter” (cd/m2), which is the intensity per unit area in a specific direction. 


During profiling, you can set different monitors to the same luminous intensity by choosing the same luminance in cd/m2. Most LCD users find that setting luminance at 120 is bright enough to judge color and detail in highlights and shadows, but if you’re having a hard time seeing details try selecting a lower value. Some calibration programs offer an option to have the software automatically adjust your display’s luminance to match the ambient room light. 


luminance vs brightness blog i1profiler


What is brightness?

Brightness is what we perceive when lumens fall on the rods and cones of our retina. When we speak of brightness, we use subjective words like “dim” or “brilliant” because it cannot be measured like luminance, but it can be scaled in percentages. 


Many displays automatically adjust brightness and contrast based on the ambient light. You can also use the monitor’s manual controls to brighten or dim the screen based on your personal preference. Lowering the brightness value will result in a darker image, while raising the brightness will make it lighter.


Why is there confusion between luminance and brightness?

These two terms are probably interchanged because luminance is the measurable quality of light that most closely corresponds to brightness, which we cannot objectively measure.


Best Tools for Monitor Calibration and Profiling:

i1Profiler is our preferred solution for monitor calibration and profiling. It is wizard-based and walks you through every step in the profiling process using either Basic or Advanced modeLearn how it works in this blog


For true mobile-to-desktop color matching on your mobile device, download the free ColorTRUE mobile app through the App Store or Google Play Store.

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