I wanted to mention two items:

• tone mapping (exposure control, poser 8 (non-pro)) can achieve a nearly linear response, like GC, when used with gain, as shown by bill in another thread
• poser 8 (non-pro) writes the Gamma and UseGamma variables to pz3, but when I tried to set these in a script, it gave an error indicating there's no SetGamma nor SetUseGamma in FFRender (poser 8 (non-pro)).  but maybe my script was wrong.