On Sun, 23 Apr 2000 17:39:23 -0500, Chris Huff
<chr### [at] yahoocom> wrote:

>I think a better way would be to implement one or several "film type" 
>post processing filters which cover physical models as well as computer 
>effects...you could have "standard computer graphics"(the current type), 
>various color films, black and white, antique sepia tone, light 
>intensity, etc.

This sounds like the idea I have, except you are suggesting creating
some "presets" to cover the more common applications. 

My primary wish was to roughly simulate a film's response curve,
ignoring color values. All three color channels would be manipulated
according to the same formula. 

If we want to get more advanced (and I think we should), we could
process each channel independently, and achieve a much broader range
of effects. Including:

1  Blue, Gold, Selenium, Sepia, or Split Toning (and many others)
2  Reciprocity Failure Simulation
3  Solarization
4  Posterization
5  Conversion to a Negative
6  Simulation of Antiquated or Alternative Photographic Processes
7  Simulation of Specific Film Stocks (the most ambitious goal)

Note: To obtain the toning effects (normally a B&W photographic
process), we would need to first convert the full-color RGB image into
a monochromatic RGB image. Then we simply alter the curves of the RGB
channels independently. While a typical POV image can currently be
manipulated like this in an image editor, it would be better to
perform such level manipulation on the raw floating point values, to
better preserve the dynamic range of the original scene.

As always, I'll be more than happy to provide more details,
explanations, and even some images to illustrate any point that might
be unclear to anyone.

Later,
Glen Berry

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