American Express 'Watch out for the watermark' by RMG Connect

American Express hired RMG Connect to help them get across the idea to companies that its new product, VPayment, could  make payment processes transparent.

Their solution was a letter which appeared completely blank, apart from an American Express letterhead, a signature and a postscript.

Curiosity aroused, the reader saw from the postscript that she needed to hold the letter up to the light. Only then could she see the body of the letter printed as a watermark.

Initial results show there was a 5.9% response rate - an 80% improvement from the average.

To download the full case study - including images - click below.