Color Random without a tile generator?

Brygelsmack

Posted this on the Substance forums but might as well give it a go here too. 

Is there any way to colorize a black and white image randomly with different shades of black and white like you can with some of the tile generator nodes in SD? 

This effect is what I'm after:

Except I want it for a pattern like this:

Is there a technique I can use to achieve this? Would really like to avoid going into Photoshop for such a seemingly simple thing.  

Thanks.

rube

With a combination of distance and edge detect on a tile generator you can get something like your example.  This video shows part of it. 

https://www.youtube.com/watch?v=f76shQFfqvI