The two main techniques
There are two methods of couching. The first, underside couching, was used from around 1250 until 1350. This technique uses a linen thread to pull a small amount of the gold thread through onto the underside of the piece of work, thus anchoring it in position. From the top the work looks as if it is covered in slight dimples where the thread has been pulled through. This has the advantage that only the gold thread is visible on the surface; all of the stitching to hold down the gold thread is on the underside of the work.

The second technique, surface couching, leaves both the gold thread and the securing thread visible. It superseded underneath couching in the middle of the 14^th century and continues to be the main form of gold embroidery used today. The passing thread is held in place by a series of small stitches of a matching or contrasting colour.

Further advances in technology brought thread that had the spiral form of the earlier metal and silk threads but has more metal so that the inner thread was no longer necessary to support it. This thread, now known as purl, could be cut into small sections of metal, which would then be sewn onto fabric as if they were beads.

The use of contrasting colour in surface couching led to the introduction of a new form of Opus Anglicanum known as Or nué, where the stitches of the securing thread are much closer together, forming blocks of colour spotted with the underlying gold thread. This was used to great effect in producing colour panels for altarpieces and clerical robes.