Reading back through my Dakka threads, I found a post about painting this marine helmet; sadly I don't have the model any more as it was a gift, but it was certainly an effective way of painting white. I'll try again when I dig all my bits out of storage.
To get a nice, crisp white helmet try the following:
- white undercoat
- Paint thinned VMC Silvergrey in the shadowy areas, leaving about 50% of the helmet pure white
- Paint some sepia wash into the recesses of the Silvergrey areas
- Paint another thin layer of sepia wash in some of the darker areas of the silvergrey once the first layer is dry
- Paint a 50/50 mix of Sepia and black wash into the very dark areas of the shadows.
The trick is not to give the full model a wash, but to just concentrate on the shadows so you leave the pure white untouched.