POV-Ray : Newsgroups : povray.binaries.images : Gamma Reference Image : Re: Gamma Reference Image Server Time
30 Jul 2024 22:28:25 EDT (-0400)
  Re: Gamma Reference Image  
From: clipka
Date: 21 Dec 2010 14:51:04
Message: <4d110528$1@news.povray.org>
Am 21.12.2010 20:31, schrieb Kenneth:
> clipka<ano### [at] anonymousorg>  wrote:
>> 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...
>
> I hope I'm not muddying the issue (or doing something stupid at my end), but
> your posted Cornell .png photograph is definitely the worst of the lot, when
> viewed on-line in the latest Firefox browser (v3.6.13): low contrast and darker
> than any of the POV-Ray images. Perhaps it needs tweaking in some further way,
> to make it a good comparison image? (I'm *guessing* that it was meant to compare
> more favorably with the gamma 1.0 image, or vice versa.)

Its dark appearance in FF may be due to the fact that the images are 
presented on a white background, and the "real thing" has much more 
black border around it; especially with the preview this messes a lot 
with the image's appearance.

As for having low contrast, that's the point I'm making: The photograph 
/is/ a physically accurate image, so if there's any tweaking to do to 
make it look like the POV-Ray renders, then the tweaking needs to be 
done on the POV-Ray side - this comparatively low contrast is physically 
/correct/.


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