The next steps of my pebble prints...
I printed large shapes with a paper stencil (cut out of newsprint with a craft knife) and smaller designs which I'd exposed on a screen coated with photo emulsion (the blue screen above), on top of the textured background I created previously using dyes on an open screen.
Making hand cut paper stencils, and choosing where to position the exposed designs by moving the screen around and blocking off the parts I didn't want to print allowed some spontaneity in the printing process. I enjoyed not planning the design of the whole picture in advance.