Clamp - Unclamp color

[Devhill]

Hi guys
what's exactly "unclamped" and "clamp" mean ???
Example for vray render element: VRayUnclampedColor - The unclamped image color.

What kind of level represent exactly ?
How can i use this element in compositing ?

I can not find a good explanation on the web.
thanks

[yakuzowner]

if you work in a bigger colorspace than 8bit ... for example 32 bit floating point, you can easily get values above 1 ... 1 stands for pure white and 0 for pure black. If you have a filmscan for example filming into the sky/sun - and you analyse the sunarea in a compositing program you will see that the pixels in the sun are much higher than 1 ... they can get values like 150 for example. When you now clamping the picture/values in your scene, your brightest points (150) will be set/clamped to 1 - so all the information gets lost. Same for superdark pixels below 0 - those will be set to 0. From a compositors standpoint I would say that VRayUnclampedColor means it stores values beyond 0 and 1 - which is good for postwork.

[Devhill]

yakuzowner thanks a lot for these info. Very clear!