Complex IOR is deprecated (it's old and you should not use it).
The Standard Surface has the complex Fresnel built-in when the metalness is > 0, using the base and specular color.
Really? Is Metalness parameter gives us physical correct IOR? For some metals or alloys its not enough two colors falloff. Do you know about measured IOR?
Can anyone tell me if the node doesn't exist in the Arnold recent updates or if it is a problem with my 3ds Max version?
Thank you! And sorry, I really thought I had checked the docs. Plus, Boris' comment made me doubt about Stephen's reply so I needed one more.