I'm reposting this info about the paint I use from another cosplay board, after updating the information of coarse.
I used water-based cake makeup from Mehron and the specific type was Paradise professional size. From this type of make-up I used a container of the color 'light blue' and two of 'lagoon blue'.
I bought these makeups from a costume store near my house. Here's a website:
Paradise Makeup AQ - Larger Professional Size
It's cheaper for me to buy them at the store, but the website offers more colors which could save time because you don't have to mix them. I'd probably recommend "sky" instead of "light blue" if you go this route.
To make the base color I took a container of light blue and lagoon blue and took and exacto-knife to them. I cut each cake of make up in half, and swapped 1 of each of the half circles to the other container. Now I have 2 containers that have half lagoon blue, and half light blue. It should look sort of like a half moon. The reason I'm doing this is because one blue is too light for the base and the other is too dark. Now that they're in the same container mixing is much easier. To apply the base to your body, add water and apply with a large paint brush. I use a 2 inch wide paint brush. I used to apply the base with a sponge, but the paintbrush is much easier. I only use one can of "base color" at a time, so I'd now have an extra one for later.
If you get sky I think it would make a good color for the base coat and you won't have to mix, which is sort of a pain. I would have probably done this if my costume store carried that color.
Water based make ups take a little getting used to, and adding second coats over large areas are hard because the water from the second coat sort of washes away the first coat, so I normally just try and do a decent first coat and leave it.
After the base coat (which takes a while) I used paintbrushes of various sizes to paint the stripes over already dried areas. For this I only used the color Lagoon Blue.
I painted everything myself except the stripes on my back which I normally have Moco Loco do.
-Other tips: Don't use nylon sponges for the base, they sort of suck.
-don't get wet unless you want the make up to come off, it comes off real easily in the shower though which is nice
- consider a LIGHT coating of barrier spray or hairspray to help preserve the paint job, if you use too much it bonds to the large amount of barrier spray and starts to flake off. I've learned this from experience
If there are any other questions, don't hesitate .