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Is it proven that the new algorithm for calculating brightness is superior to the old one?

From: WCAG 2.0 Comment Form <nobody@w3.org>
Date: Thu, 31 Jan 2008 17:21:49 +0000 (GMT)
To: public-comments-wcag20@w3.org
Message-Id: <20080131172149.31EC36B5EA@tibor.w3.org>


Name: Michael Zapp
Email: redaktion@bitvtest.de
Affiliation: BIK (barrierefrei informieren und kommunizieren)
Document: W2
Item Number: Success Criterion 1.4.3
Part of Item: 
Comment Type: general comment
Summary of Issue: Is it proven that the new algorithm for calculating brightness is superior to the old one?
Comment (Including rationale for any proposed change):
The Techniques For Accessibility Evaluation And Repair Tools (W3C Working Draft, 26 April 2000) suggested an algorithm for calculating the brightness of an RGB value. Empirical surveys were conducted on this for verification and the algorithm was and still is actually used in practice.

In this old algorithm the RGB-components were weighted as follows:

0.299 * R + 0.587 * G + 0.114 * B

The suggested new calculation of brightness uses a different weighting, namely:

0.2126 * R + 0.7152 * G + 0.0722 * B

Was the old algorithm faulty? And if it wasn\'t: is it proven that the new algorithm is more appropriate in this area of application?

Proposed Change:
Proof for the superiority of the new algorithm for the calculation of brightness.
Received on Thursday, 31 January 2008 17:22:02 GMT

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