Color Impact 2023 was a great success. These pages are left here for archival purposes.

We hope to see you at a future Color Council meeting! Our next conference in June 2025.

June 11-15, 2023

Rochester Institute of Technology, Rochester, NY, USA

Presenter - Luke Hellwig

Luke Hellwig, Senior Scientist and Researcher

The Brightness of Chromatic Colors

As a visual stimulus becomes more colorful, it appears brighter, even if its luminance remains constant. This phenomenon is known as the Helmholtz-Kohlrausch (H-K) effect. We present a key innovation in the traditional method of brightness matching used to psychophysically measure the H-K effect. The new experimental method allows for a calculus-based approach to modeling brightness-matching data, which in turn provides novel insights into the mathematical relationship between colorfulness and brightness. These insights lead to a new model of the brightness of chromatic stimuli, fit to the results of a series of three brightness-matching experiments conducting using our novel technique. The model is incorporated into the CIE color appearance model (CIECAM16) and the CIELAB color space, allowing for its use in a wide range of applications.


Luke Hellwig is a Senior Color/Vision Scientist at the Samsung Display America Lab and a PhD candidate at the Munsell Color Science Laboratory at the Rochester Institute of Technology. He previously received a BA in Physics from Carleton College and was awarded the Ruth Katzman Award at the Art Students League of New York. His research seeks to improve the validity, utility and rigor of models of color appearance.

The Inter-Society Color Council advances the knowledge of color as it relates to art, science, industry and design.
Each of these fields enriches the others, furthering the general objective of color education.


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