I use ,Daler-Rowney, Georgian artist oil paint, lamp black..Longer open time to work it in and it cleans up easily and color is very good. I was told of this by a man who owns the Scrimshaw Work Shop in Bar Harbor Maine,he is also a well known Scrimshander,,I have use the inks in the other posting on this subject,, all work, it's like scrim tools, try them till you get the one you like best ,,then go with it,,,
If you open the site Mark posted it will become apparent he knows what he is writting about ,,