For broad-pen writing, I add gouache to Higgins Eternal. Gouache gives Eternal some needed body. It doesn't necessarily have to be black gouache. Indigo or a dark red add an interesting hue to the result. In a quarter ounce of Eternal, I add about a 3/8" bead of gouache from a tube. Eternal doesn't give me the hairlines I want in pointed pen work, so for that I much prefer iron gall or walnut ink.