Understanding Red Albedo Indicator

[chartensimage]

Hello.

Why Corona shows "too bright albedo" starting from 217,217,217 value when having just diffuse component active in material? Why is it 217? My question is: Shall I consider RGB 217,217,217 as a theoretical 100% albedo value or 100% albedo is simply RGB 255,255,255?

Thanks

[TomG]

Here's a discussion on albedo in one of the videos:

(not sure why but it didn't start at the time in the link - 11m 27s or so is a good place to start if the video plays from the beginning for you!)

And an article on it on freshdesk:
https://coronarenderer.freshdesk.com/support/solutions/articles/5000515614-what-is-albedo-

Basically, nothing in the real world reflects 100% of incoming light (which is what 255,255,255 would represent), and any such unrealistically high value will introduce noise and slow down render times.

[chartensimage]

Hi TomG,

Thanks for your help but what I want to know is if the red albedo indicates maximum theoretical albedo value of 100% or something below? Because if it represents maximum value the 0.5 albedo in this scale would be RGB108.5,108.5,108.5 (0.5*217=108.5).

In the scale where 255 corresponds to 100% albedo, the 0.5 albedo would be RGB 128,128,128.

Does anyone knows for sure? Thanks.

[mferster]

yes a material w/ diffuse level 0.5 - 255, 255, 255   is equivalent to a material w/ diffuse level 1.0 - 128,128,128.

That multiplicative relationship applies to all corona material attributes that use both level and color values

[maru]

Theoretically there is nothing wrong in using 255 albedo, provided that you know what kind of effect you are about to achieve, and that you are aware that the rendering will be much slower (especially in case of large surfaces such as walls).

The albedo elements shows:
-saturated red - in areas that have definitely too high albedo for realistic/fast rendering
-slightly reddish/pink - in areas that are somewhat too bright, but will not cause that much trouble

I am not sure about the specific values which are indicated. Let's find out...

[maru]

It looks like it's starting to become reddish about RGB 237.

[Jadefox]

Is there any reason why one would have a colour and level scale
ie: Why have 0 to 1 on the left and have RGB level on the right ?

Would it not be more user-friendly to just have a sRGB indicator
I know one could argue just keep level on 1, but as soon as that value gets changed we have to
pull out the calculators.

This would be applicable to all the other denominators, why not have a material system where we just
use a single variable

Hope the above makes sense

[romullus]

I hope it will stay as it is. I hate controls by by colours - it takes longer to setup, it's hard to tell its exact value, it has inconvenient range. I use it only when i need to change hue.

[SharpEars]

It looks like it's starting to become reddish about RGB 237.

OK, so the magic RGB triplet to stay below is 237,237,237 (or 237 for the brightness, if HSB is used).