Physical black material appears white

[MircoTosti Studio]

Hello guys,
i don't know if i'm doing something wrong but how come in a 100% black material with 100% roughness (therefore not reflective), the result is a white material under a hdri day light.
If instead I use a legacy material that is always 100% dark, this appears black.. as it should be I think.

Thanks in advance to everyone

[romullus]

100% rough does not mean that material is not reflective, it means that its reflection is completely diffuse. If you want non reflective physical material, you also need to set its IOR to 1.0

[MircoTosti Studio]

Romullus, tnx for the reply.
If I wanted to make an asphalt, like in reality, if I use the texture of a dark asphalt with ior at 1.. this however always appears white.
What's the best approach to making asphalt so it doesn't turn white?
I put an example with the dark asphalt texture of megascans (if i try to use the cosmos material for the asphalt it comes out totally white even though it is dark grey).

hence also the doubt/advice on how to avoid that in an external situation in daylight the textures and the image correspond to the built materials and do not appear "washed out" or white

[romullus]

I thought you want non physical black material, like black hole. If you want to create physically plausible material, like asphalt, then tampering too much with its IOR is definitely bad idea. If your materials are too bright no matter what, then most likely that your exposure is too high. Also you may want to use some sort of tone mapping - by default Corona should use Aces OT which i find gives pretty good results out of the box.

[MircoTosti Studio]

if you see the attached image I already use an AceOT.. the problem is that the "black" texture of an asphalt taken from MegaScans renders it clear. The same goes for the asphalt material (dark grey) that you take from the Corona Cosmos which gives it back to me totally white.

[Beanzvision]

Hi, can you send us a test scene for this? When using the same asphalt texture from Cosmos, I'm getting the following result.

[romullus]

It's exposure. I suppose you're using Corona sun and sky and your exposure is set to 0 - that's way too high for daylight and unless you changed sun and sky intensity from default, it will massively over-blow your scene. Correct exposure for sun and sky is somewhere between -3 and -4.5 depending on sun position and other factors.

[MircoTosti Studio]

Romullus, I used hdri from corona cosmos browser day018 hdri, setting its expo at -4 from color correct shader.
I share the scene on Beanzvision's bug report, thanks for all the valuable info

[MircoTosti Studio]

Hi, can you send us a test scene for this? When using the same asphalt texture from Cosmos, I'm getting the following result.

Tnx for all and your patience Bengamin

Submission ID# 5VUD-MWAW
Render DayLight goes white texture (dark).
Also, textures downloaded with the "triplanar" check from cosmos browser become glossy and do not match textures downloaded without the "triplanar" check enabled.