Darn, gamma was where I was going next <g>
Actually, that might explain why somebody else had
different constants. Default gamma is different on
Macs and PCs. Images made on one system would
probably need different constants from images made
on the other system.
--
-Richard M. Hartman
[EMAIL PROTECTED]
186,000 mi/sec: not just a good idea, it's the LAW!
Tom Zerucha wrote in message <29939@palm-dev-forum>...
>
>On Mon, Nov 13, 2000 at 01:31:57PM -0800, Richard M. Hartman wrote:
>> It would help if we knew what the constants represented ...
>
>> -Richard M. Hartman
>> [EMAIL PROTECTED]
>
>The constants represent the relative luminance of each color. If the
>same number of photons hit your cone cells, they will appear brigher
>or dimmer based on color. That is one reason a green laser pointer
>can go two miles where an equally powered red one only goes 1000
>yards. (Your night vision is more sensitive to blue than red, but you
>don't see color, so I am not talking about this - in the day on a
>white wall...).
>
>The numbers represent the mixing proportions of red, green, and blue
>to produce white. Though the differences may depend on the
>"temprature" of the white, normally given in degrees kelvin. A body
>heated to that temprature will give off that proportion - 6000k is
>much bluer than 3000k.
>
>Most monitors have such settings and there are pages and pages of
>things on the internet about this (don't get me started about Gamma
>correction - I didn't do it for PiNGer and don't want to).
>
>> Tom Zerucha wrote in message <29837@palm-dev-forum>...
>> >
>> >On Fri, Nov 10, 2000 at 04:53:17PM -0800, Alex Pakhotin wrote:
>> >> Hi Hans,
>> >>
>> >> gray = 0.299*r + 0.587*g + 0.114*b
>> >
>> >I think the equation I use has slightly different constants.
>> >
>> >I do this for PiNGer (the viewer for ZBoxZ - GPL OpenSource
>> >palmboxer.sourceforge.net) to display color PNG and GIF files on
>> >grayscale palms.
>> >
>> >
>>
>>
>>
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