im just wondering how you would go about making this texture overlay in photoshop. im familiar with masks and blending modes but i just cant get it looking right. any help would be great. cheers
There are many ways to achieve this grunge wall affect, but the easiest way to achieve this would be to create the colour layers first or backgrounds (ie: in your example, the blue brush stroke, the black brush and the gray image).
Then what I would do is create a layer on top of those and use a grunge brush over them in a black shade. You may want to lower the opacity afterwards so it doesn't overpower the BG
There are so many grunge brushes out there, deviat art is a great place to find them. Something like this: http://www.deviantart.com/browse/all/?section=&global=1&q=grunge+wall+brush
Then I would sugest playing around with blend layers like levels and curves to get the darkened areas to appear better.
With these kind of things to get the best results, you should do as many individual layers as you can, and overlay them so they blend in, that's basically what this person has done and then you can get some really nice work.