Best Reflectivity Coating for Headlight Reflectors

In the restoration of antique automobile headlight reflectors, the question arises as to the best plated finish . Is there a source that shows scientific data as to the reflectivity of silver, aluminum, rhodium, nickel , chrome.

Nickel is not highly reflective, and chrome is worse; these are not good candidates. Aluminum is inexpensive and used on millions of reflectors of all types. But silver and rhodium are more reflective. Rhodium is probably the ultimate, but is very expensive, more difficult, and probably wasn't used originally on antique automobiles. I'd go with the silver. See letters 1533 and 2122.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

Hello, I hear that Rhodium (Rh) is a very reflective metal, but I can't find any graph on it's reflectivity index and at what wavelengths is most reflective at. Can someone guide me in the right direction.

Hi guy's further to the question the industry standard for all modern cars i.e., after using actual silver and since the 60's is vacuum metallising with aluminium, this is a 3 sandwich layer with a high temp base coat a .05 micron aluminium layer and then a clear top coat also heat resistant.