In your freshdesck website you have considered:
0.70 μm for Red, 0,55 μm for Green, 0.45 μm for Blue
But for wideRGB gamut like that:
https://upload.wikimedia.org/wikipedia/commons/1/1d/CIExy1931_AdobeWGRGB.png
Green belongs to 0,52 and blue 0,390. why is there this discrepancy?
Thanks
I don't believe input values can be absolute, most approximations around the limits of the visible light spectrum will work just fine depending on, as said previously, "preferred visual outcome and on how much oxidation is introduced on the metal's surface" (excluding metal alloys - impure metals - although oxidization implies impurity, but let's just leave it at that).
Let's take the example of Pure Gold (Au) - Generally, its electrons move at relativistic speeds (especially on its outer surface). The outer surface is responsible for its chemical behaviour and a lot of physical properties, including color. The human eye spectrum
varies from wavelengths - approximately 390 nm (blue) to 700 nm (red), gold absorbs a lot of the low wavelengths (blue). So we’re left with the opposite (yellow - towards red when it's pure).
Pure Gold (au) does not get oxidised, hence pure gold should not appear green-ish, it should mostly reflect yellow with a minuscule tint of red. The following comparison showcases exactly just that, Complex IOR of Gold with 0.7-0.55-0.45 against sRGB limited values of 0.61-0.56-0.47:
https://corona-renderer.com/comparer/RRnUev (Both outcomes can be described as Gold, but when thinking of recreating Pure Gold we should compensate for corresponding wavelength inputs, in order to remove the greenish tint)
So, to summarize, any approximations between
0.70 μm for Red, 0,55 μm for Green, 0.45 μm for Blue (~ +- within reason) will work great for most pure metals, in some cases, you might want to experiment with different wavelengths. I hope this helps, and it actually makes sense!