Further work on my experimental piece this week. Not quite finished yet but getting close.
Here is the piece after doing the following.....
To add the black background smudges I first cleared an old formica table top (any smooth surface would do) and taped registration marks for the piece. The areas where I did not want the smudges were masked off with freezer paper.
Then black pigment was painted on to the table surface, the piece turned over and rolled down on to the black pigment. The result is as seen in the first photo.