playing around with the mr photographic exposure control, I found a way to get the backgrounds “almost untouched”.
Select the mr Phographic Exposure Control, and ajust the Exposure Value (EV) or Photographic Exposure to get your image correctly lighted.
Set the physical scale to “UNITLESS”. The value here, will be the result from the next formulae:
(note: EV is the value you get from the Exposure Value (EV), even if you used Phothographic Exposure, and the Exposure Value (EV) is greyed out…)
Unitless value = PI*(2^EV)
EV = 0
Unitless value = 3.14 * (2^0) = 3.14 * 1 = 3.14
EV = 1
Unitless value = 3.14 * (2^1) = 3.14 * 2 = 6.28
EV = 10
Unitless value = 3.14 * (2^10) = 3.14 * 1024 = 3215
What will mess up a little bit your picture, will be the Image Control…
But I found some values, that works when you have gamma off (have to look for some others when you work with gamma 2.2, 1.8, etc)
Color saturation: 1.0
Whitepoint: 100.0 (YES!, 100!!)
To probe this, I post here a snapshot from the RAM player with two pictures, the left with mr Photographic Exposure Control, and the right one without control. You will notice the background (a gradient) is the same on both pictures. I used the ramp, to be able to adjust the subtles differences on the midtones.
So, it would be REALLY nice, if the “Process Background and environment maps” control, would do this automatically… Or at least have a button that calculate all of this!!!
Well… I hope this helps you. And I’ll be waiting for comments and suggestions for better techniques.
(sorry for my bad english…)