Traditional underside couching sample worked on linen with silk floss - began at the bottom of the photo and had a bit of difficulty finding the exact same hole to go back into but this got easier as I progressed. The stitching is 1.25" X 2.5"
Underside couching on canvas - this was much easier and I enjoyed doing it. I especially liked the effect on wrong side - hence the second sample
From left to right - Lurex thread couched with blue stranded metallic thread, thin metallic ribbon, greed cotton perle and lurex thread, machine thread with lurex.
I found the underside machine couching difficult; it was hard to get enough contrast using the size of the stitch alone. As you can see I had more success with the thick cotton thread in the bobbin than with the gold thread.