Diffuse Values Above 70%

[kmwhitt]

Something I don’t understand about the more recent versions of Corona for C4D – It seems that you need to bump up the white values of the diffuse channel to avoid getting gray materials and renders.  Even the material library comes with materials that break the rules.  In earlier versions I was told never to exceed 70% in value for the diffuse channel as this would be physically incorrect.  Does this not apply to newer versions of Corona where the material libraries are supposedly PBR?  Further, the Physical Material has 73.536% as it's default value which I assume is what most are using for quick clay renders?

[romullus]

Corona material's base colour default is 50%, not 73% Don't forget that you need to look at linear values if you want to know what's being fed to the engine. If you're working with sRGB values, then the safe range is about 12-90%

[kmwhitt]

Romulus - thanks for the quick response.  That's according to who you're talking to.  The folks at substance define this "safe" range somewhere between 30% and 75%.  The out of the box physical material under base layer defaults to 73.536% as shown in my attached image.  I am using Cinema 4D and have linear workflow checked and the color profile is sRGB.

[kmwhitt]

meant to say depending on who you're talking to...  not according!

[romullus]

I think you're simply mixing linear and sRGB here. Your friends from Substance most likely have in mind linear values (linear 75% translates to sRGB 87,7%), although 30% seams way too high in whatever range.

I can't tell with 100% certainty what values are shown in your screenshot, but i suspect that they are sRGB (sRGB 73% translates to linear 50%). Remember, renderer always operates with linear values and sRGB is here mostly for user's convenience. You always need to be aware with what values you're operating. If it's sRGB, then safe range is about 12-90%, if it's linear, then range is 2-80%

[kmwhitt]

Thanks Rom.  That is what's confusing to me.  I haven't used Corona in a couple years and now that I'm picking back up, I'm not sure if I have Cinema 4D setup correctly.  As I don't think you're a C4D user, I was hoping someone could advise on the C4D settings in the attached image.  Further, is there a calculator that exists somewhere to convert linear linear to sRGB?  I'm concerned that the value I'm using for white walls is too dark at 70%; however, not sure if I'm working with linear or sRGB in the first place.  If I am indeed working in sRGB that would explain why my white walls appear gray and it is necessary to ramp up the light settings to get decent light.  I'd really appreciate someone helping me understand this.  Thanks again, Kevin

[piotrus3333]

good read:
https://www.fxguide.com/fxfeatured/game-environments-parta-remember-me-rendering/

[Nejc Kilar]

Howdy!

If you've got C4D set up to have sRGB as the input color profile then yes the values you see are sRGB. Try setting the input color profile to linear and you'll see the previews will start looking brighter (because 73% white in linear is "whiter" than 73% in sRGB).

In C4D things can get a little bit confusing because if you're using a renderer that uses the built in node editor then that one by default has the Linear values toggle turned on for whenever you are picking colors with it. And that toggle overwrites your input color profile - but again, this is only true for the C4D node editor (and possibly only in the last few versions). The classical node editor (and our Corona Node Material Editor) are respecting the input color profile option.

[kmwhitt]

Thanks Marcin.  Good read...

[kmwhitt]

Nejc - Thanks for the detailed explanation.  I guess I've been using Corona incorrectly in the past with my diffuse values too low.  The results I'm getting now are much better.