Speaking to the Herald from his home in Medford, New Jersey, Mr Salvage said his wife, a high school counsellor, was a reluctant model but even she was inspired by New Zealand's beauty.
"Ten minutes into the Routeburn Track we turned the corner to a waterfall and right in front of us was a giant rainbow. I thought, 'God, I hope she's in the mood' and she looked at me and was like 'Where's the dress?'."
Mr Salvage said they hoped to head to Thailand, Cambodia and Singapore next year to continue the project. The dress has already been to Egypt, Norway, Iceland, Moscow, a Hawaiian volcano and Greece.
They do have a "dirty secret", though - the US$400 ($480) dress has a double, so the original isn't ruined in extreme conditions.
See more at the couple's One Dress, One Woman, One World website.