Forum: Poser - OFFICIAL


Subject: Why do I need Gamma

aRtBee opened this issue on Oct 17, 2011 · 76 posts


bagginsbill posted Tue, 18 October 2011 at 9:17 PM

Quote - But if you use G=1.0 and export as non-HDR file, arent you're lacking the information to do a good GC in postwork? If you export as HDR or EXF you still have the nessesary information in the image, but these files are gamma corrected when you cut them down to a viewable dynamic range. 

Am I wrong here?

I was hoping this would become clear that you're right without me having to do it. It seems I'm always being argumentative. But you're right. And I discussed this twice before in GC threads. I'm sorry but truth is truth.

There is the zero-data problem. A lot of your data maps to 0 - you cannot pull out anything from a pile of pixels full of zero. This is not just black - many colors have a component so close to 0 before gamma correction that they never come out right in postwork. And then there is banding - where many slightly different levels end up in the same integer.

Basically, the rule is you want to get the levels as close to their final values as possible before you export to 8-bit for postwork levels adjustment.

That usually means that the linear, uncorrected version is exactly not what you should tell people to use, artbee.

Demonstrations of zero data and banding are here:

http://www.renderosity.com/mod/forumpro/showthread.php?message_id=3652928&ebot_calc_page#message_3652928


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