Jona: Sorry to take so long. Cellophane can add the color, but it won't want to make the compound curves to cover the visor. That said, you could try shrinking it after you apply it by using a heat gun to shrink out the wrinkles, just like the RC airplane guys do with the plastic wing coatings (Monokote).
-Redshirt
thank you sssooo much!! This tutorial is really helpful. I was thinking about applying the cellophane with my vacformer, but it might be easier to use a heat gun. I am looking at doing this for my eva helmet so this will be a bit easier. awesome helmet btw!!