M Y N D E X
Supervising Color Science Researcher: Andrew Somers
Color Vision Deficiency Simulator (CVD Sim)
NEW: CVD Simulator. We developed this new web app to simulate how someone with Color Vision Deficiency** sees the world. We accurately simulate Protanopia, Deuteranopia, and Tritanopia. We also present an experimental model of Blue Cone Monochromacity. www.myndex.com/CVD/
**Color Vision Deficiency is sometimes referred to as "color blind," though that is not accurate except in some very rare cases.
Please be advised: The experiment pages listed below are using fonts sized in REM and are thus NOT responsive. They are intended for desktop/laptop use, or use in our test app.
Live Contrast Experiments 2019
Brief Commentary on Contrast
and the WCAG Accessibility Standards.Interestingly, the W3C/WCAG math is similar to a basic Weber contrast in terms of a perception curve when in a totally DARK environment (such a bedroom at night). Of course the described problems are present in typical and high ambient lighting.
One of the curiosities with the WCAG math is the addition of a 0.05 "flare" component to both sides of the simple contrast equation:
(L1 + 0.05) / (L2 + 0.05)This appears to do little except distort contrast by marginally pushing ratios slightly toward 1:1 (if you eliminate the L luminance terms, you get 0.05/0.05 = 1:1).
It is not a particularly useful way to boost contrast or limit low contrast. While it does help to slightly enhance contrast in dark color pairs, dark color pairs is where the overall WCAG still fails most, especially in high ambient lighting conditions. Indeed this math generates some contrast figures that are ultimately illegible in real world conditions. (Paradoxically, the math also rejects some color pairs that seem perfectly legible).
Hwang-Peli's Modified Weber adds the flare component to only one side, the denominator, as:
(Llight - Ldark) / (Llight + 0.05)In our experiments in real world conditions (including mobile devices) we've found that an offset of 0.1 is more useful than 0.05 :
(Llight - Ldark) / (Llight + 0.05)I discuss this modified Weber in this post in the GitHub discussion. This method provides a superior and more robust contrast assessment than the current WCAG methods.
Advances in Perception: Our ongoing research is working with a new set of equations & algorithms that are based on human visual perception. Beyond providing a reliable and robust assessment of contrast for accessibility guidelines for graphically rich web content, we anticipate further development of the concepts will lead to better environmental responsiveness for computer display devices in general.