I enjoyed the crude way of achieving this: I applied gold leaf to a gooey layer of etching ink with alkyd. I then drew into the gold leaf with a utility knife. Savage.
The fragility of gold leaf is remarkable: all you have to do is lightly, very lightly, touch it and it tears. Supposedly, a leaf is about 500 atoms thick.
Confession: what I enjoyed most was the image resulting true enough.
Collection of Pamela Murray