Question

thingiverse

You All know these sunglasse with gold and silver mirror colored glasses in them, you can perfectly see through them though nobody can see your eyes? Well this isn't a post on a make or something but more of a question: If I would like to make a Helmet with a visor (Spartan from Halo, Daft Punkt Helmets....) what is the process called for that sunvisor coating? I have looked up various terms on coating and gold and silver coatings but all I get are non-seethrough or Opaque....well you're practically blind wearing the helmet or you have a clear visor, how do I do this? What is the process called? The only thing I could find is from Nasa where they actually coated the visor in a thin layer of gold but no How to's? The STL is from @Big_red_frog 's Halo Visor