What surfaces except metals have colored reflections?

[Rens]

None that I know of, but things like certain paints/coatings and some coloured textiles such as silk have coloured reflections as well because of metals used in the paints.

[marque-pierre]

Everything is everything. A blue object will have a slightly blue shadow and reflect slightly blue light, and so on. All objects do that. Perhaps very subtly, but still.

[playmesumch00ns]

None. Materials are either dielectric (don't conduct electicity, e.g. glass, water) or conductive (do conduct electricity, i.e. metals).

The surface reflection of each type is modelled by a particular specialisation of the fresnel function. Dielectrics reflect all wavelengths roughly equally, so have white reflections, while conductors reflect wavelengths differently, resulting in coloured reflections.

The reflectivity of various different conductors has been measured, and the data can be used to generate a pretty accurate reflectance curve for those materials. These are the so-called "n-k" data available for use in Maxwell and other renderers.

[mister3d]

None. Materials are either dielectric (don't conduct electicity, e.g. glass, water) or conductive (do conduct electricity, i.e. metals).

The surface reflection of each type is modelled by a particular specialisation of the fresnel function. Dielectrics reflect all wavelengths roughly equally, so have white reflections, while conductors reflect wavelengths differently, resulting in coloured reflections.

The reflectivity of various different conductors has been measured, and the data can be used to generate a pretty accurate reflectance curve for those materials. These are the so-called "n-k" data available for use in Maxwell and other renderers.

Thank you all for replies.
Playmesumch00ns, I heard that any surface has a fresnel reflection, but I thought that metals don't have fresnel. at least I never set it to fresnel, just to simple reflection, without faloff.
And you want to say that wavelengths in conductors are bending in different directions chaotically, that's why they are colored?
And how about those accurately measured reflectance curves, is it used broadly in videoproduction? I may be wrong, but having unbiased values is a bit limiting? Do these values may vary In real life yet?

[soulburn3d]

Playmesumch00ns, I heard that any surface has a fresnel reflection, but I thought that metals don't have fresnel. at least I never set it to fresnel, just to simple reflection, without faloff.

Metals do follow the fresnel equations, it's just they have a very high IOR, and hence reflect reasonably evenly over the entire surface. Objects with a lower IORs favor a stronger reflection at the glancing angles.

And how about those accurately measured reflectance curves, is it used broadly in videoproduction?

They aren't used that frequently, but a few studios have used them now and again.

- Neil

[playmesumch00ns]

As I said, the fresnel formulae for metals and non-metals are different. While reflection on non-metals gets brighter at glancing angles, on metals it often tends to get darker, as well as displaying colour shifts (copper is a good example).

I'm using it for metallic stuff here. It's a subtle effect but does make it more realistic.

[Gephoria]

What surfaces except metals have colored reflections?
really, alot of things from a designer point of view i wanna say blundtly "anything you choose" but reallistically speaking it could be anything from colored water, certain wood/polishes, tinted glass, a bad eraser on a pencil when they get useless and shiny and smooth, but most of all, mountain dew!

i hope this helps, doing secondary refractions is tuff

[mister3d]

Isn't iridescence has a colored reflection too? http://en.wikipedia.org/wiki/Iridescence

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