Can anyone give me advice on how to use Holbein Duo Aqua Oil water soluble oil colors?

If you used regular linseed oil, that's probably your problem with the tackiness and the paint running. According to what I've read, to thin or help blend your water soluble paint you would "Blend with water or Duo Painting Oil. Duo Aqua Oil dries in as little as 24 hours and may be used with up to 30% of traditional oil colors. Combine with other water based media for various results. Mix with water to achieve a uniform Matte finish and with oil for a uniform sheen" Holbein makes their own Duo Aqua Oil, or Artisan linseed oil, of which you only need a drop or so, so you grab some with just a toothpick. Some recommend that you use a few drops of Windsor Newton water mixable painting medium and a tiny amount of water to get water soluable oil colors to a workable texture. Sources: <a rel="nofollow" href="http://www.jerrysartarama.com/discount-art-supplies/online/2147/art-supplies/5">http://www.jerrysartarama.  more