Hiding text in a photo

[Overread13 1]

So I'm curious if anyone here knows of a way to hide text within a photo so that it won't appear unless the photo is edited in a limited form - eg posterized. I'm essentially doing an online scavenger hunt and I'm looking for ways to hide information within an image. Attempts to make it very very close to nearly the same colour as the surroundings in the past lasted about 5 mins before people found the text. So I was wondering if there's a way to do it so that it can't appear unless the photo is adjusted.

 

[Rickbb63 1]

I've not tried it, but this looks like it would do the job.

Invisible or Visible Watermark? How to Make One for Free

Learn how to make invisible watermarks for your images in PhotoShop and how to make invisible watermarks for your video online for free.

www.flexclip.com

 

[smoke665]

I tried the method suggested by @Rickbb it does work, though you'd have to be able to view it in a software capable of separating channels.