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Re: Color Contrast - where to measure?

for

From: Patrick H. Lauke
Date: Aug 16, 2023 8:47AM

On 16/08/2023 15:09, Mobley, Mary Lou via WebAIM-Forum wrote:
> It depends on the context. If there is a photo or graphic underlying
the text, then the eye dropper tool is more accurate than the hex codes
or RBG, as those will not accurately calculate the
foreground-to-background contrast as they cannot discern the background
color in these contexts (this is why automated color contrast checkers
are often wrong). But if there is a white background or a colored
background available in the code, then the coded RGB / hex codes provide
a more accurate way of measuring contrast.

Yes, the difference here is that if it's text that is part of a bitmap
image, it's "baked into" the image, so not at the mercy of the user's
antialiasing/font-smoothing settings, nor is it zoom/size dependent (to
an extent anyway). Whereas for actual HTML (and SVG) text, all those
factors can play a role.

Not to mention potential issues with colour profiles set by the user
(depending on how the colour picker works, it may pick the colour
*before* the profile is applied, or *after*, and the latter then makes
it even more subjective/variable to make a pass/fail assessment)

P
--
Patrick H. Lauke

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