starting with a 52% gray background, create a new layer, make whatever shape(s) you want, using pure white. Here I've made one simple greeble shape.
When you have all the shapes you want, duplicate the layer, and hide the duplicate.
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With the original shape layer selected, click the layer style button (Looks like an 'F' or an 'S' in a circle) and select "Inner Glow".
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Change the color to black, the blend mode to Multiply, and the technique to precise.
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Click OK. You should have something similar to this:
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Create a new blank layer. Merge it with the current layer. This incorporates and finalizes the layer style, so MAKE SURE you are happy with the style before you do this step.
The purpose of this is so that we can set the layer's blend style to Lighten or Screen so that our greeble will only displace out. We can also control how far it displaces by adjusting the layer's opacity. This allows us to create multiple layers of greebles. I've set the opacity of this layer to 51%.
Depending on which blend style you choose, the results will differ:
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I've chosen screen to continue with.
Here I've created another layer of greebles using the previous steps, setting the opacity to 80%:
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I also raised the displacement percent from 250% to 300%.
Now, I'm going to show you why we saved those untouched copies of the greeble layers!
Hide the greeble layers that we used for displacement. Create a new layer, beneath the untouched greebles. Pick two similar grays, and Filter:Render:Clouds. Then Filter:Artistic:Sponge. (Adjust to taste. I tried to get very small details.)
Here's the result:
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Rather metallic, yes?
Now, turn on the lower greeble layer, and go to Layer Style:Outer Glow. Use the following settings:
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Now Right click on the layer and select 'Copy Layer Style'.
Right click on the higher untouched greeble layer and pick 'Paste Layer Style'. (Note you can also save layer styles by clicking on 'New Layer Style' from the Layer Style Settings Palette. I've saved both of these styles for later use. )
again select the lower layer. Create a blank layer above it, and merge them. Repeat for the upper layer. Set the Blend Style for both to 'Multiply'. Adjust the opacity to taste. Here's what I've got:
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Now here it is as a color map:
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Here's the project and all the files:
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And here are the Layer Styles. They go in the Photoshop:Presets:styles directory.
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