Anti Gamma Correction
Exposure Correction as well as Gamma Correction are straightforward, well defined adjustments of the render result. So far so good. Only … Exposure Correction just comes as such while Gamma Correction (GC) in Poser and Vue is the final part of a tandem. The first part of that tandem is the application of Anti Gamma Correction (AGC) on the definitions of lights, colors and materials before rendering. This part is far less understood, Poser and Vue perform it differently, and it comes with a shipload of artifacts.
The reason for applying AGC at all is the following. First the texture is anti-corrected, then the rendering adds highlights, shading and shadows. Then the result is corrected. In the end, the highlights, shading and shadows come out corrected (that is: softened), while the texture itself remains more or less intact.
- In Vue, external image-maps are anti-corrected but internal color swatches are not. So an object colored from an image-map and an object colored from an internal color that look similar without using GC, come out differently when GC is applied. Of course all internal colors can be adjusted and Vue provides proper tools for that, but then the reverse will happen: they will behave similar under GC but different when GC is not applied.
The details are presented in the Vue chapters (part I, part II).
- In Poser, external image-maps and all internal color swatches are anti-corrected, but color values are not. So an object with (50%,0,0) in the colorswatch and 100% in the value will come out different from an object with (100%,0,0) in the colorswatch and 50% in the value, when GC is applied (PoserPro) – and will come out similar when GC is not applied (Poser). And there is more to be concerned about.
The details are presented in the Poser Pro chapters (part I, part II).