I started by base coating them a solid, dark blue.
You can see the little guy on the left is just blue. The guy on the right has already had the next step applied: gently airbrushing some royal purple colour over it. I dilute the first transition colour enough that it takes a few quick passes to get an opaque coverage. Then I paint from the outside/edges of the model in, so that the outside has the most layers and thus the strongest purple colouring, and the inside the least. You can see below that it's a nice smooth transition.
I get annoyed spraying very thin paint through my airbrush (because I'm impatient when it comes to waiting for things to dry) so I mix my paint with a distilled water : matte medium 1:1 mix. This way it gains transparency, but I do not have to thin it more than I would a colour I wanted to be opaque. (Matte medium is thick but see through).
Once I had been round the edges of the main bodies I started on the tails. I want to have more than one colour transition on this so decided to have everything going to white/blue towards the back. I started right at the tip with a 1:1 mix of magic blue (VGC) and water. As I got closer to the purple and blue already on the model I thinned the colour more to get another smooth transition. I really like the VGC magical blue colour. It's very pretty, strong, and has a great texture/consistency. One of the best Vallejo paints, I very much recommend picking it up, especially if you've got an airbrush. (What with it being in a dropped bottle.) I added a couple of drops of dead white, and thinner to keep the consistency the same, and began to mist progressively less and less of the tails until I reached nearly white tips.
Now came my first ever attempt at freehand! I looked up some runes and started sketching them out on one of the models tail using my original deep blue colour. I made sure my paint was very thin, and using a 00 W&N series 7. My paint was thin enough that it was nearly dry by the time I got to the end of the line. Once I'd gotten shapes I like, I filled the lines in with a smaller layer of dead white, trying to keep some of the original line showing on the outside.
Where this didn't happen I just went back over or around the white with the original colour. It was a back and forth for a while until I got shapes I was happy with. Now with the base done, I have to work out how to make them look like their are glowing. I probably shouldn't have chosen blue for my first attempt at this, because blue is a solid opaque pigment and notoriously difficult to layer with!
But the OSL is a matter for tomorrow. Today was a bad lot for just a couple of hours of painting.