Webpages and visibility

[Kurt Wolf]

I have been watching this topic.  Interesting enough.  At my office  
we try to keep a couple guidelines for colors.  The formula below  
calculates the brightness of a color.

((Red value X 299) + (Green value X 587) + (Blue value X 114)) / 1000

By computing the brightness of the foreground and background, we try  
to keep the difference between these two values greater than 125.   
This is also found on the W3's site.

Two colors provide good color visibility if the brightness difference  
and the color difference between the two colors are greater than a  
set range.

Color brightness is determined by the following formula:
((Red value X 299) + (Green value X 587) + (Blue value X 114)) / 1000
Note: This algorithm is taken from a formula for converting RGB  
values to YIQ values. This brightness value gives a perceived  
brightness for a color.

Color difference is determined by the following formula:
(maximum (Red value 1, Red value 2) - minimum (Red value 1, Red value  
2)) + (maximum (Green value 1, Green value 2) - minimum (Green value  
1, Green value 2)) + (maximum (Blue value 1, Blue value 2) - minimum  
(Blue value 1, Blue value 2))

The rage for color brightness difference is 125. The range for color  
difference is 500.


On Sep 6, 2005, at 11:48 AM, FoulDragon at aol.com wrote:

> In a message dated 9/6/2005 11:47:09 AM US Mountain Standard Time,
> eculbert at yahoo.com writes:
>
>
>> PS. Red Seven's page wasn't that bad, A few shades
>> more white and yes it would have been almost
>> impossible for me to read.
>>
>
> Select the text and read it that way.
>
> You often see spoilers posted in white-on-white on fandom  
> discussion sites.
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