On Fri, 17 Nov 2000 18:40:42 -0500, Chris Huff wrote:
>In article <chrishuff-9268FA.17205617112000@news.povray.org>, Chris 
>Huff <chr### [at] maccom> wrote:
>
>> I'm not sure which conversion is used... I will check this out later...
>
>The GREY_SCALE() macro is used, which uses the function:
>Gray = 0.297*R + 0.589*G + 0.114*B
>I have changed this to use (R+G+B)/3 in my version.

For pure grayscale values (R==G==B) the results are identical.

E.g.: 

0.33*0.297 + 0.33*0.589 + 0.33*0.114 == 0.33
(0.33+0.33+0.33)/3 = 0.33

I suggest leaving GREY_SCALE() as it is.

	hp

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