Home > Basic Products > Bister > Powertex Bister 250 ml Powertex Bister 250 ml Ref. 0046 Price €7.50 Add to cart Powertex Bister is a ready mixed very dark brown water-based liquid patina to use in combination with Powertex Ivory and Terracotta. Bister is not waterproof and always needs to be finished with Easy Varnish.