Colofilter.css - Duotone filters made with CSS !
More info at http://lukyvj.github.io/colofilter.css
You can check this codepen collection using colofilter.css : http://codepen.io/collection/AGpJpm/
If you need to make colorify works with
background-image please, take a look at : This codepen demo
( But I'm about to update colofilter.css to make it easier to work with background images )