Thanks guys!
Uff! Done 
It was a bit of a marathon last night, but I was able to complete "The Prototype".
Here you can see where I started yesterday evening.
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I then added more grime and more shadows.
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After the shadows I began painting and spraying the light effects.
First only on the walls
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Then also on the Siglinde and the other pieces.
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After the white lights I added yellow to warmen the light and to simulate the light bulb effect.
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The little neon light in the back and on the desk remain white
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And the welders got a blue-ish light.
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Done!
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In the light box.
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And the final images.
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I hope you like it 
It's been fun - quite a different thing than my usual settings.
I look forward to your C&C.
Cheers
Klaus