Linear Workflow problem in Reflection Glossiness texture slot

[f2b]

Hello,

C4D scene setting: Linear Workflow is On, input Color profile is sRGB

Render is different when i replace de 0.5 Glossiness numeric value with a 50% grey bitmap. Please see attachments

I only get the same result if i apply a gamma 2.2 with a filter on this bitmap


-> This problem dos not exist for Reflection color numeric valus vs. bitmap
-> This problem dos not exist for bump

Maybe i have miss something? Actually it seems to be a "bug"

Regards

[christian_schneider1]

Hey,

This behavior is somewhat to be expected.
Since Glossiness is a a linear value, the bitmap it gets fed needs to be interpreted as linear too, to get the same color-value compared to the numeric-value you change directly in the reflection options. You can do that in the VRayBitmap-Shader. There you find options for TransferFunction and RGB Primaries. With those you can change how the incoming bitmap is used - in your case the bitmap transfer function most likely needs to be changed to linear to get the result you want scince you dont need any color correction.
Bitmaps are always intepreted as sRGB images - so they get corrected. Same should apply to the bump channel - it would be helpful if you have additional info how you tested that or you could share a scene.

Make sure to read the documentation for more information (Bitmap Node)

[f2b]

ok, personnally i use c4d bitmap shader, so i will have to set input to linear in this one. I can work this way, if it's really the intended way
I just hope this exception for glossiness will not be changed in few month, and so i will need to convert again shaders in our objects library.

i'm already converting shaders from vray 3.7, and i'm scripting all this kind of repetitive stuff... juste want to avoid to process my library twice