I have long used, with good effect, the AK color modulation kit for 4BO. I have gotten the hang of airbrushing the acrylics. Recently, however, I had the pleasure of spraying Tamiya thinned with their lacquer thinner. I am hooked.

Does anybody out there have a good cookbook for mixing an equivalent range of 4BO colors to create a good modulation effect?

I have seen recommendations for a a 50/50 mix of Olive Green and Khaki as a base coat for 4BO. From there, add white, flat yellow, dark yellow, and or sky to the mix to make it lighter.

Ammo of Mig Jimenez also makes a modulation set for 4BO, and their paints spray very well. If you decide to use these paints, make sure you apply them in thin layers, allowing them to dry before applying the next. Shake the bottle very well, and always paint over their own brand of primer.

I did a bit of digging on this only just recently & came up with this mix from Mil Mod site: 40-60% yellow ochre, 15-20% zinc chromate, 10% ultramarine and 10-20% white.
I suspect this was using Humbrol or Revell enamels. Translating into Tamiya acrylics, I used Lemon Yellow for the yellow ochre, made my own mix of zinc chromate with yellow-green & black & used flat blue for the ultramarine. The result 'seems' a little light in colour (almost a light pea-green) but with filter & wash, may still be OK.

HTH

I use Tamiya Field Grey(It's really green). For modulation, I add yellow and tan to my taste. I think it's spot on and have been using this mix for years.