The following images show the Cornell University's famous "Cornell Box" 
reference scene for 3D rendering...

(1) as a photograph taken from the "real thing" at Cornell University, 
using sophisticated calibrated equipment, at a wavelength of 600nm; the 
original is an OpenEXR image; I applied linear brightness adjustment for 
more contrast and converted to PNG for convenience, which shouldn't hurt 
its fitness for serving as a reference image, but if in doubt you can 
compare with the original 
(http://www.graphics.cornell.edu/online/box/box_exr.zip).

(2) as a POV-Ray 3.7 render using geometry, surface reflectance and 
light source data as published by the Cornell University 
(http://www.graphics.cornell.edu/online/box/data.html) for a wavelength 
of 600nm, using "assumed_gamma 2.2"; light intensity was adjusted in an 
attempt to obtain a similar overall brightness as the photograph; notice 
how the side walls still appear much too dark while some other areas are 
already too bright.

(3) ditto but with gamma-correction applied to the color values; notice 
how this fixes the relative brightness of the surfaces, but otherwise 
still leaves the image with a much stronger contrast than with the "real 
thing".

(4) using the original color values again, but without "assumed_gamma". 
The brightness of the light source was adjusted by exactly the same 
factor that the photograph had been brightened; no other parameters were 
tweaked. Notice how the "real thing" is simulated pretty faithfully.

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Download '600nm.png' (1639 KB) Download 'cornell_gamma22_raw.png' (95 KB) Download 'cornell_gamma22_adjusted.png' (112 KB) Download 'cornell_gamma10.png' (89 KB)

Preview of image '600nm.png'

Preview of image 'cornell_gamma22_raw.png'

Preview of image 'cornell_gamma22_adjusted.png'

Preview of image 'cornell_gamma10.png'