Re: Suggested edits for guidelines 1.4 CONTRAST

Hello Gregg,

This is easier to understand and to be tranlated than the old definition.
It was hard for me to understand this definition when I tried to
translate it into Japanese.

<blockquote>
> luminosity contrast ratio 
> {{(L1 + 0.05) / (L2 + 0.05), where L1 is the luminosity of the lighter of
> the text and background colors, and L2 is the luminosity of the darker of
> the text and background colors.
</blockquote>

I think we'd better say:
- lighter of the text "or" background colors
- darker of the text "or" background colors

If we say "and", they look like "both the text and background colors" to
me and it is confusing a bit. In the old definition, it said "the higher
value (of text or background)". I just want to clarify what we mean by
this definition. 


Cheers,
Makoto


On Wed, 22 Feb 2006 01:38:23 -0600
"Gregg Vanderheiden" <gv@trace.wisc.edu> wrote:

> 
> 
> Here are some suggested edits for the WCAG Contrast guideline Definitions  
> 
> They are to clarify some ambiguous parts but do not change the guidelines.
> 
> 
> Gregg
> 
>  -- ------------------------------ 
> Gregg C Vanderheiden Ph.D. 
> Professor - Ind. Engr. & BioMed Engr.
> Director - Trace R & D Center 
> University of Wisconsin-Madison 
> The Player for my DSS sound file is at http://tinyurl.com/dho6b 
> 
> 
> Note:  All modified content segments are enclosed in double braces {{}}
> 
> 
> definition for "luminosity contrast ratio"
> 
> 
> [old definition...]
> 
> luminosity contrast ratio 
> {{(L1+.05) / (L2+.05) where L is luminosity and is defined as .2126*R +
> .7152*G + .0722B using linearized R, G, and B values. Linearized R (for
> example) = (R/FS)^2.2 where FS is full scale value (255 for 8 bit color
> channels). L1 is the higher value (of text or background) and L2 is the
> lower value.}}
> 
> [end of old definition]
> 
> 
> [new definition...]
> 
> luminosity contrast ratio 
> {{(L1 + 0.05) / (L2 + 0.05), where L1 is the luminosity of the lighter of
> the text and background colors, and L2 is the luminosity of the darker of
> the text and background colors.
> 
> The luminosity of a color is defined as 0.2126 * ((R / FS) ^ 2.2) + 0.7152 *
> ((G / FS) ^ 2.2) + 0.0722 * ((B / FS) ^ 2.2). R, G, and B are the red,
> green, and blue RGB values of the color; FS is the maximum possible full
> scale RGB value for R, G, and B (255 for eight bit color channels); and the
> "^" character is the exponentiation operator.
> 
> Note: Luminosity values can range from 0 (black) to 1 (white), and
> luminosity contrast ratios can range from 1 to 21.}}
> 
> [end of new definition]
> 
> 
> 
> 
> 

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Received on Friday, 24 February 2006 14:43:08 UTC