What color paper and ink cannot be copied?

[Hulk]

Just like the title says, what color paper and ink cannot be copied?

I have some documents I want to share with my employees but I do not want these documents to go externally out of the office.

I have heard that blue ink on blue paper cannot be copied, but I have not tried this yet so I am unsure. I don't want these documents to be copied on a black or white or color copier.

If this is not possible to do with colored paper/ink do I need special paper or ink?

 

[pxc]

We use black printing on dark-ish red paper at work, but that only thwarts B&W copying.

Almost any combination of colors can be copied on a color scanner/copier though. If you don't want someone to copy easily, you don't print it out. There are ways to prevent most copying from a screen if the computer is moderately locked down, but then someone could use a camera phone (which are B7 where I work).