In the 1930s women often painted just the center of the nail, leaving the moon and tip bare. Filling in the whole nail with color was considered an extreme look. Nice girls didn’t do it! A whitening pencil was used on the back of the nail tip as well, like this one from Sally’s Beauty Supply.
According to this very informative site on vintage makeup, common nail polish colors in the 30′s included red, pink, deep coral, lilac, emerald green, cornflower blue, gray, gold silver and even black!
There are two ways to re-create this vintage moon manicure. Leave the half moon, or moon and tip, completely bare, or paint a lighter shade on the whole nail, let it dry, then apply the darker shade over it.