In article <TUgDOeHcwtbl7VCZwbG2XphrPOQ2@4ax.com>, Glen Berry 
<7no### [at] ezwvcom> wrote:

> If I remember correctly, Nathan said that the rendered image exists in
> floating point format before it is converted to the final image
> format. Would it be possible to gain access to the floating point
> values? I'd like to be able to specify my own formula for converting
> the floating point value to an 8bit integer.

This shouldn't be hard...I think all of the post-processing is done 
before the final clipping to the 0-1 range.(don't take that as reliable 
information though, I am just guessing)


> Why? I want to alter the linearity of the translation from floating
> point to integer. If you look at a plot of photgraphic film's response
> to light, it isn't linear. There is a certain threshold that must be
> achieved before any image is recorded.  Above that, the response is
> somewhat linear, until we get to the brightest exposure levels. In the
> highlights, increasing the exposure has less and less of an effect.
> 
> In other words, the darker picture elements are expanded in dynamic
> range (higher contrast), and the brighter elements are compressed in
> dynamic range (lower contrast). One of the effects of this would be
> the ability to render light sources and not have them "wash out", or
> lose detail,  quite so easily. I think that adjusting the response
> curve to approximate film would also make the image look more
> realistic in general. 

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.
Also, I think the post_process stuff really belongs in the camera, not 
global_settings. This is just personal preference, though...

-- 
Christopher James Huff - Personal e-mail: chr### [at] yahoocom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Personal Web page: http://chrishuff.dhs.org/
TAG Web page: http://tag.povray.org/

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