When I'm coloring snowmen most times I use BG0000, BG000, 0 but I've also used G0000, G000, B000, 0 for snow scenes and especially icicles.
Well, I mostly just use B0000 and B00 around the edges and in shadow areas.
I use the same colors for snow as I do for coloring things white: B0000, B000, B01. B01 for the darkest parts & shadows and then blend it out to white with the other two colors.
I would use B0000 & B00 for icy areas, BV20, BV23, BV25 for a darker purple shadows, E40, E41 for a warmer snow and C0 for light shadows... I would blend heavily with my colourless blender to blend and push these colours out. A little clear spica glitter enhances the snow glistening too!
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