How can you thicken acryllic paint?

Question: How can you thicken acryllic paint!?

What can you add that's safe for the painting!.
It needs to look professional, so it can't effect the longevity of the painting!.Www@QuestionHome@Com

Best Answer - Chosen by Asker:

You can purchase gels that are specially made to thicken acrylics made by the same companies that make the paint - Golden, Liquitex, Grumbacher, Winsor & Newton etc!.

http://goldenpaints!.com/products/medsadd!.!.!.Www@QuestionHome@Com