- From: Andrew Somers via GitHub <sysbot+gh@w3.org>
- Date: Mon, 20 Jun 2022 14:59:48 +0000
- To: public-css-archive@w3.org
> What is SmrsModWbr? I assume it is a modified Weber, got a reference? "Somers Modified Weber" is a further offset and scaling following an idea from Peli/Hwang's Modifed Weber, and I indicated that was from a series of evaluations in 2019 of various contrast maths. I abandoned it as it does not track the full range very well, and reverse polarity is also sketchy. The thing with Weber and Michelson contrasts is that they track at very low, threshold contrasts, but they do not predict what happens at supra-threshold readability levels, and the difference is significant. Maureen Stone (PARC, NIST) and Larry Arend (NASA) had written about using ∆L* for luminance contrast, and in some experiments adding in scaling and offsets, that avenue began to indicate the shape of the perception. This led to greater consideration of CAMs and perceptual models, notably CAM02, R-Lab, Barten's model and Hunt's model. When you consider that viewing a self-illuminated display and reducing to luminance (as that is the parameter essential for readability) this allows a subset of CAM input conditions, permitting a reasonable simplification to determine luminance & stimulus size-based readability contrast via perceptual lightness/darkness difference. -- GitHub Notification of comment by Myndex Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/7357#issuecomment-1160554446 using your GitHub account -- Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config
Received on Monday, 20 June 2022 14:59:50 UTC