For pt/pd prints I use natural white and for silver I use bright white. For metal sectional frames I use either silver, matte silver, flat black or contrast gray for silver prints and for pt/pd a German silver (a warm matte silver) frame. For wood frames I select from the framer's samples or use a museum frame in a warm black that he blended which works for both pt/pd and silver.
On the occasions of having an exhibition I try to keep one color of frame for all. If metal sectional and both pt/pd and silver prints I would use the German silver and if wood the warm black.