I did say that I wanted to test the new Belladonna Black Diamond when pulled out into very fine strands - as it is supposed to stay a true black.
The thicker black lines, above, you can see them on the side of the bead closest to you, were from stringer about 1.5 - 2 mm thick.
These thinner lines were from stringer that is literally thinner than a hair - whippy, bendy thin. To pull these, melt your gather of glass, not a very big one, and then pull very fast. Careful where you put them down. If you put them down directly on the bench, you may not be able to see them, or even to pick them up again.
To use stringer this thin - don't put it in the flame. Heat the bead to a light glow, and lay the stringer down on the bead, out of the flame, letting the heat of the bead attach the stringer to the bead.
Anyhow, you can see - the stringer has remained black, although a little less saturated in a couple of them - but no hint of purple.