Color Mapping Frustrations

[hereagain]

Can anyone give a simple explanation of when and where the different color mapping selections are to be used? I am trying to render an exterior daytime scene with linear multiply, which looks good on darker materials, but anything light gets burned out. If i switch to HSV Exponential, everything gets dark and looks incorrect. Does it matter what your light source is (i.e., Vraylight, Vraysun, HDRI, etc?) Thanks for the help.

[Brian Smith]

Try using Reinhard and adjusting the Burn value. Start with 0.5 which is a blend of exponential and linear. Move it closer to 1.0 to make it more linear and move it closer to 0.0 to make it more exponential. The light source doesn't matter...it's the illumination hitting the surfaces that matters.

[only3d]

parden my "jumping in" on the thread but its exactly the same subject so i thought it would be appropriate/

 

so like my freind from above i cant get the jist about colour mapping...

im an intelligent person, looked for as much info as i could, and made hundreds of experiments (not a single checkbox i havnt marked or unmarked!)

and still im having problems with it.

 

ive learned that exponential is kinda the way to go so i tried it, got a lighting configuration that i like and then i find out that glass materials get all messed up cuz of it!

for some reason the glass gets dark and distorts the background image.

no-matter what i do it doesnt come out right and it really bums me out...

so any ideas anyone???

 

heres a capture of what im talking about

[Brian Smith]

i'm pretty sure it's a gamma issue but i can't say for sure because i haven't ever had this problem and haven't looked into before. i always use an object to display the background. is there some other problem besides seeing an incorrect background color?

[only3d]

i actually know what causes it and u r right on the money!

its the 'affect background' option under exponential, and because ur using an object instead of an environment bitmap u dont have that problem.

well i knew that before but what i dont understand is why?

plus yeh i can check that option and supposedly "solve" the problem but then it completely changes the background colour.

 

not that im too spoiled to tweak with the bg colour untill i get it but i dont get the logic.. its not an object so why would it b influenced by the lighting?

and even funnier- how come it happens with 'exponential' but not at all with 'linear multiply'?

i just dont get it.. and its getting harder & harder to explain to my students as we go deeper into vrays depths...