reflectance for plastic all 1,1,1 ?

[michalfratczak]

I just noticed that albedo values for all plastics are 1,1,1 - that doesn't sound correct ?

[AntonPalmqvist]

When it comes to transparent materials it should be interpreted as Transmission Color.
The API is designed so that the Color field can be used for either albedo (dielectric), reflection color (conductor), or transmission color (transparent).

The idea behind setting Transmission Color to [1, 1, 1] on those plastics is that they're representing a generic transparent plastic, without dirt or color tint.
There can of course be many different variations of these plastics, but I chose to represent a perfectly clean, transparent version where you can easily see the difference in IOR.
I have also not found any reliable data on transmission color and attenuation for these kinds of plastics, so for the time being that perfect, transparent, value is the closest I can get.
An alternative would be to just not show the color value for these materials where no measurements are available.