Using the integrity dark I have had to style several backgrounds that were not fully black they are slightly grey. I have found one that I can not find the class to change it to black.
On the product pages under the product description you will see a couple grey lines like shadows or outlines that I would like to remove or make black. http://jeffdillon.involve.media/product/test/
I have attached a zoomed in screen shot so you can see it because on most monitors it looks black but it is not.