|This is "bobbin work" with a sewing machine. It was done with a 7.5 mm long stitch length on an Elna 9000. That machine, along with the Diva, 8000, and 6000 had a 'bypass' hole in the drop-in bobbin casing that accommodated bobbin work "sew" beautifully. I haven't seen (personally) a machine since that had this long of a stitch length and could do this work with 4 mm wide silk ribbon as beautifully. I took no extra care in winding the silk onto the bobbin - done by machine, just letting ribbon slip through my fingers to hold somewhat straight, but not caring if it twisted or not.
Here is a close-up view: