learning to control the ink

I did a double-run print today, experimenting with opaque paints and the idea of an underlayer to a top-layer composition. The two plates are on the left in the photo, the underlayer plate at top and the "drawing" plate underneath. At the top right is the intended print, clearly too dark with too much ink. At the lower right is a single-run print that I took off of the already printed "drawing" plate, with an interesting atmosphere but not my original intention.

In principle, my method worked. The underlayers did show through, as I wanted. The problem was in the second plate, whose colors were too close in value and too heavily laid down to give the effect I sought. How to lighten up that second plate? Thinner layers? Greater distinctions in value? Clearer marks?

This was done in Gamblin relief ink.