White camo with acrylic paints?

I've used Vallejo's model air acrylics quite a bit on figures, brush painting.  When I've done a section of white (a t shirt, a helmet) I'll start with light grey.  I work some medium greys into the crevices and perhaps a touch of dark grey.  What I'll often do with the white is mix in a small amount of yellow to give it some age, and then using very thin paints, or Vallejo's mediums mixed into the paints, cover everything with light layers of white.  I find the touch of yellow worked for me, it might not work for you.  A pale tan or brown might also help with aging, though I've never tried it.  Perhaps a little of each in different areas?

Citadel paint is fantastic for this kind of painting!

Speaking of Vallejo acrylics, they offer a boxed set of whites specifically for painting uniforms. Contains everything you need for deep shadows, midtones, and highlights, along with SBS instructions on how to use the set. Essentially, the paints are premixed per the advice given by ajlafleche above and the results are pretty convincing.

Start with light gray. Use darker grays for neutral white. Add a bit of blue for cool white, light browns for warmer white. Continue with the tones in your highlights, saving pure white only for the highest highlight. Search TIMELINESFORUMS for Dan Capuano's (dancap3286) w
ork. He is one of the best painters around and uses Vallejo acrylics.

Hello Leddy,

White camouflage is hard to paint realistically. Enamel based flat white paint covers better therefore will be a better choice over acrylics.

   Prime the figure with flat white then consider how 'used' you will like the figures fatigues. Reference photographs show after a short while the uniforms become very dirty. Grays or browns work best for the shadows, possibly both if a worn a lot look is desired. The trick is to keep the white theme without it becoming a washed out gray or brown. Use enamel flat white for the highlights, Testors has a flat artic white that is a good choice. Less is more with the darker shadow colors.  

   Look at other modellers work and see what worked or didn't on their winter themes along with the reference photographs.