You can find the new controls in the Imaging tab - please try it out and post your results, plus any suggestions you might have!
Indigo for Windows 64-bit:
Indigo for Linux 64-bit:
Indigo for Mac OS X (10.7 - ):
Indigo RT for Windows 64-bit:
Indigo RT for Linux 64-bit:
Indigo RT for Mac OS X (10.7 - ):
* Added colour curves to the UI.
* Changed Phong and Glossy transparent materials to have roughness instead of exponent parameters.
* Added some backwards compatibility exponent->roughness conversion and support code.
* GPU PT: Added support for constant emission (multiplier) spectrum mat params.
* GPU PT: Added maximum bump map normal angle, in line with CPU behaviour.
* GPU PT: Added support for absorption_layer_transmittance for specular.
* GPU PT: Made normal map texture evaluation skip quadratic func and gamma, like on CPU.
* GPU PT: Added support for non-transparent specular
* GPU PT: bump mapping and normal mapping should work now for specular mats.
* GPU PT: Fixed missing clamp on Fresnel scale for Phong
* GPU PT: Handling bump and normal maps on blend root materials.
* GPU PT: Handling scattering from blends with delta materials properly.
* GPU PT: Added meanCurvature() ISL support, just returns zero for now though.
* GPU PT: Fixed handling of minCosTheta() and maxCosTheta() in ISL functions.
* GPU PT: Added support for single-wavelength eval ISL shaders.
* GPU PT: Converting float textures to 8 bit for now.
* GPU PT: Faster kernel builds with nk-data phong.
* GPU PT: Phong should converge faster.
* GPU PT: Fixed problem with backface of geometry being black.
* Fixed issue with diffuse material and minCosTheta() etc..
* Fixed constant emission (mult) parameter on background material erroneously giving a 'Only constant or texture emission parameter supported for background material currently.' error.
* Made halt time and halt spp spin boxes not apply settings while being typed in.
* Saving some memory when saving to tone-mapped EXR format is not used.
* Fixed a possible crash on memory allocation failure.
* Performance optimisation for blends of null and non-transmitting materials.
* Added back meanCurvature() ISL support in displace params, at least for the blend material case.
* Fixed shadow pass.
EDIT: Here is an example of the curves at work, showing the curve UI, as well as the effect on the render: