Resistor compositions are disclosed, made from polymer thick film resistor formulations comprising a polyimide component, a sterically hindered hydrophobic epoxy component and a solvent component having a Hanson polar solubility parameter between 2.1 and 3.0 and having a normal boiling point between 210 and 260.degree. C. The weight ratio of polyimide component ("A") to epoxy component ("B") is A:B, where A is between and including 1 to 15 and where B is 1.