How to Find Authentic Armour Helmets Images for Replicating Them for LARP & Reenactments

We are a group of metal smiths and love to replicate finest antique armour helmets with details. We need to find rare images of historically accurate armor helmets and other metal items for recreating them.

We have replicated some designs of Viking helmets but are not sure if these are historically accurate or are just work of fiction.

Any suggestions on how we can get information about historical armour apart from the wiki. Museum images are a good source but pretty expensive,