Help proxy cards - distinct fake?

[VidarThor]

Hello, this is my first time on the forum. I am sorry if I am asking a wrong question.

How to I make good looking proxies that can be detected as fake?

I have found how you make a good foil proxy by making an emty foil and printing on plastic paper. However I would like to add like a watermark or something to make sure people distincivly do not know it is real. Do anybody know how I do this?

For those of you wondering about the backround, a local gaming club wnats to run an all proxy non sactioned legacy tournament. I was considering attending but only if I get good looking proxies. I do not want to play 75 paper pieces of magic in sleeves.

sorry about bad spelling, I am dyslextic.