Color gradient controlled by specular highlight

Hello!

I’m in the process of creating a complicated flat material. It is similar to a colored mirror with a thick transparent plastic like cover on top (thickness ca. 5mm). Recreating this material seems to be very difficult to me, because of the very strange interactions with the light source.

To make it easier, I’ve just assume we only have one light source (sun) and are reasonable far away of the plane object. The end result color now seems to be correlated by the reflected light and the angle of view. Direct reflection of the light source into the camera shows the main color and with increasing angle between the two vectors we get another color fading into a base color.

The solution to recreate this material could be to calculate the angle between the reflected light vector and the camera vector. That’s why I’ve asked this question here: How to get the reflected light vector in Cycle Renderer?

Another way, without any calculations, could be to control a color gradient by the specular highlight of a material. But I have no clue how to achieve such an effect.

Could anyone point me towards a solution? Thank you!