I'm sorry to jump in, i have an somehow unrelated question, and please bear in mind i am very nontechnical. I still haven't understand completely how corona settings works for materials.
So, should i understand that i can input values like 0.0234 or with even more decimal ? I'm asking because i'm just a user, so for me , in my head it was working more like 0.1- 0.2-0.3 up to 1. It this high precision for all the settings in materials or just for Refl? Please excuse me if my question is stupid, but reading this thread, i can see that i actually have no idea how to make accurate settings for materials. Maybe also the reason for my poor materials. Is this also for diffuse? I could use a value of 0.17263 and make sens ?
If none of this makes sense, don't complicate your life. Some of the articles linked in this thread explain all that's discussed, don't ask for tl:dr notes.
But matter of fact, no, none of it is important, you don't need to use any numbers and absolutely not such small minimal decimals.
Here is simple (/simplified) guide to live by:
Non-metal: Keep everything default (Ior: 1.52) and create textures that suite your look. Some materials can be more reflective (up to 2+) like plastics), some are less (1.333 like water), but you can still keep it default.
Metal: Keep Ior between 4-to-40 +/- (the simplest way without using curves or anything to setup exact specular curve of metal).
Adjust Glossiness using 0-to-1 and textures how it looks good to your eye.
That's all the number you need in nutshell. You don,t need any 0.2122475 magic to make something look real, you missunderstood this thread.