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On Site | Monitor Luminance vs. Brightness


by Brenda K. Hipsher – January 8th, 2011

by Brenda K. Hipsher

Ever wonder what the difference is between the terms luminance and brightness?  These terms are generally used in connection with the light level output of a monitor or display.  We know that having this brightness or luminance level set correctly is a big part of a screen to print match so that we can predict what prints will look like whether we’re printing at home or sending to a lab.

On XritePhoto.com there’s a tab at the top called Learning. Within that tab there are selections for all kinds of things like How-to Videos, the popular Color IQ Test, links to live Webinars on the schedule and On-Demand Webinars archived for your convenience to watch day or night.  AND there’s also a section that contains Commonly asked HelpDesk Questions (currently called Tips and Tricks). That’s where we find the answer to today’s question under For My Monitor.

Here’s the question: What is the Difference Between Luminance and Brightness?

And here’s what it says, “Luminance is the luminous intensity, projected on a given area and direction. Luminance is an objectively measurable attribute. The unit is ‘Candela per Square Meter’ (cd/m2). So, different monitors can be adjusted to the same luminous intensity by measuring the luminance in cd/m2. To learn more about Luminance, visit www.crompton.com.

Brightness is a subjective attribute of light. The monitor can be adjusted to a level of light between very dim and very bright. Brightness is perceived and cannot be measured objectively (but scaled, e.g. in %).

So, what is a colorimeter or spectrophotometer doing when it adjusts the Brightness? It is evaluating the black point, which is the starting point for the Brightness curve. Two black patches, which are very close together, will be measured. The best level for the Brightness has been found, as soon as the measurement device can measure a slight difference between the two black patches. The Brightness level would be too low, if no difference is measurable, and it would be too high, if the difference would be too big.”

On this same page you can find other quesitons like:

Can a Colorimeter Profile an LED Display

Difference Between LCD and Laptop Selections

Monitor Profile Doesn’t Load Automatically on my PC

What is Meant by the Term “Observer Angle”?

Windows Defender – Turning Off & On

Visit the Learning tab at www.xritephoto.com often and explore all the great information we have just waiting for you there.  We’re constantly updating the info so if you don’t see what you need leave a comment here and or contact cmsupport@xrite.com for more information or specific assistance.

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Categories: Displays, Education, Lighting, News, On Site, Perception | Tags: , , ,

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