IOR VS Reflection Amount Chart

[-Ben-Battler-]

Hi there

Yesterday we talked about IOR and reflection amount in this topic:

And I always find it hard to estimate the amount of reflection at a specific IOR, so I decided to create a chart where one can see the relations between the two in a straightforward fashion.

I didn't find anything similar on the web but maybe I was looking in the wrong places. When someone has other sources for this, please tell here!

[ikercito]

Looks interesting but i don't really see the way to implement it... Could you elaborate please?

[dubcat]

Here is my secret Cheat Sheet.
I have updated it with sample values from Corona 1.4 (2016-02-06 Daily), in case there have been ninja fixes.

Plastic = 2-5% reflectance = 1.3 - 1.6 IOR
Gemstones = 17% reflectance = 2.4 IOR

[-Ben-Battler-]

Wow, awesome!

Funny that you our results differ tremendously from each other.
You reach 50% @IOR 6, me on the other hand @IOR 2.7. Did I some huge mistake there or am I just unable to read your table?

I created a scene, RGB 255 Environment, Box object, orthographic viewport facing a side of the box, rendering and colorpicking the rendered grey values while adjusting the IOR of the box's diffuse lacking fully reflective material.

[dubcat]

Hey man, I've been afk the last couple of days.
I got 91 flat planes that rotate from 0 to 90 degrees.
"Environment Map" is pure White and the material has Black diffuse.
I render front view in orthographic, select the "CESSENTIAL_Reflect" element and sample the 0 degrees plane.

You can do this quick calculation and compare it with the sampled data.
Reflectivity = ((1-IOR)/(1+IOR))^2

Example:
Reflectivity of 1.5 IOR = ((1-1.5)/(1+1.5))^2 = 4% | Corona 4.03%
Reflectivity of 50 IOR = ((1-50)/(1+50))^2 = 92.31% | Corona 92.90%

Edit:
Siger ThinFilm just for fun



and here is the difference between "1.0 Reflection" and "0.5 Reflection"