In this tutorial I will be teaching you the basics of creating a wall texture that would suit a game such as Half-Life 2.
First start by making a new document, texture size of 1024×1024 pixels (we’ll resize it later.)
Now open up a stock photo of a rocky wall, I used this one.
We’re going to give the texture a bit more detail by adding in another texture.
First get another stock texture image and lay it over the current, you can download the second image I used from here.
Blend this second texture in to the first by changing the layer mode to Soft Light and maybe lowering the opacity if you see it needs it.
Looks like the image could do with a little brightening up!
Go to Layer > New Adjustment Layer > Levels… and use similar settings as to mine:
Should look like this right about now: