Re: [APML] Film Tri-Color Filters?

[SHEKHAR@prodigy.net]

>
>If you're talking about converting color to 
grayscale in Photoshop,
>that is not the same as adding the three channels. 
Photoshop does
>some kind of a conversion that tries to simulate 
what a color image
>would look like in grayscale. I believe it is biased 
towards red.
>
> Chuck

This is a good point.  There is a distinct difference 
in what Photoshop displays monochromatically when you 
are looking at the red channel vs. what you get if 
you save the red channel and convert it to 
grayscale.  In the former case, Photoshop is showing 
you the combined luminance and color information, 
whereas once you convert to grayscale, all you have 
left is the luminance information. In other words, 
once it is converted to grayscale, the color 
information is lost and all you have left is the 
luminance portion.

This resulting grayscale image CAN NOT be used as the 
red channel in a tricolor image.  This is a subtle 
yet very important difference.

Chuck, I think the image is biased towards green 
because green has the highest luminosity amongst red, 
green and blue.

Shekhar




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