metal & rust

you should have a certain knowledge of photoshop if you want to make this tutorial. if you don't know about layer masks, layer otions and other basic photoshop knowledge you may have some problems with this one. i will add some easier tutorials later, if i see that many people don't know what i'm talking about.

make a new file, use the clouds filter (filter -> render -> clouds) (make sure that you back and foreground color are black and white).

adjust the brightness/contract (image -> adjust -> brightness/contrast) so that the image looks similar to pic1.

make a new layer and fill it with white. add some monocromatic noise (filter -> noise -> add noise) (about 50). use the motion blur filter (filter -> blur -> motion blur) in horicontal direction with an intensity of 30. now go to the layer options and choose multiply.
now for the rust: duplicate the layer, add some noise (50 or so) and emboss the whole thing (filter -> stylize -> emboss) play aroud with the settings. i used 138°, 2 pixel height and an ammout of 152%. now use the hue/saturation (strg+u) to colorize the whole thing in a decent yellow / brown tone (depends on which rust you want to have).
now add a layer mask on the rusty layer and apply clouds in the layer mask.use brightness/contrast to sharpen the mask.

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the rust was a bit too light for me, and so i changed the layer options to multiply, and added another layer with the rusty texture and a different cloud mask.

note that this is only one alternative to make metal and rust, there are various others out there, some are a bit easier, but i tend to use this alternative. for exact rust positioning don't use clouds in the layer mask, just use the airbrush tool to paint the rust where you want it.