Hi Fuzzy,
Cheers! It was actually quite simple to do, but you need an airbrush with a fine needle. I have a Iwata HP-BH...not cheap, but works well.
1. I first sprayed the OSL areas with a medium green tone (VMC Park Green Flat). You don't really need to be careful here as the overspray actually gives the OSL effect.
2. Mixed some Vallejo Model Air white with the Park Green Flat and sprayed in the first part of the flow. With the grills, try to keep the spray as much inside the grill. Not too much of a problem is this is slightly sloppy.
3. Use pure Vallejo Model Air White and spray the brightest spots.
4. Take yellow ink and spray over the green and white. The white makes sure you get REALLY BRIGHT yellow. This works much better than spraying with yellow paint.
5. Take some green ink and spray the shadow in the lower parts of the bigger pieces. This ensures you get good contrast.
For the purple areas I did a similar thing. First spray everything a very light purple (purple ink + white). Then use purple ink to add the darker tones, leaving the glowy parts whitish.
I hope to do your Martian Walker too someday with similar techniques
. It's still one of my favorite Martian Walkers and I MUST paint it someday.
@Dave: you're on