I have long been on a quest to make a dark, non-asphaltum based softground.  I call my ground ‘darkground’ because it is far more opaque than traditional softground as asphaltum is replaced with a soy-based litho ink. This, my most successful recipe, is based off of William Fairthorne’s recipe in the 1662 publication “The art of graveing and etching: wherein is exprest the true way of graveing in copper.”  It is the oldest English language book in the subject, a fun read, and can be accessed free here [link opens in new window]. 

Ingredients, measured in ounces by volume. Click for links:

- 1 1/2 ounces of wax
-1 ounce powdered gum arabic 
-1/2 ounce of Hanco Archival Litho Process Black
-1 ounce of vaseline, any will do

Instructions:

Use a coffee grinder to grind the gum arabic to a fine powder.  In a double boiler, melt the wax.  Stir gum arabic into melted wax until it is thoroughly incorporated.  Finally, mix in the litho ink.  Keep the mixture at just below boiling for ten minutes so that all elements are well incorpated.  Remove from heat and stir in the vaseline while the mixture is still hot.

Darkground can be stored at room temperature for many months either in ball form or in a jar.  Application is similar to any other ball ground; in my experience, it is not affected by overheating.  I prefer a slightly heavy application (see illustrations below).  

I etch with a vertical tank and Edinburgh etch at 28 baume.  A 35 minute etch gives a wonderful read of drawn marks, a 15 minute etch is sufficent to pick up most texture that is run through a press.