Whipped back stitch

Whipped back stitch makes a heavier line than a back stitch. It gives a similar effect to a stem stitch but a touch finer with the added bonus that it can be stitched in two separate colour threads if required. This technique is useful when a raised line is required on a fabric which is too delicate for a heavy thread to be embroidered directly through the weave.
For more background see the entry for back stitch.
Method
First, work a foundation row of back stitches ensuring each stitch is equal in size and not too small.
Using a second thread, whip over this line from right to left, as shown, without picking up any ground fabric. Use a blunt-ended tapestry needle for the whipping thread to avoid splitting the foundation stitches.
Continue whipping along the line. Notice the benefit of having slightly larger foundation back stitches allowing the tapestry needle to pass easily under each stitch.

Structure of stitch
Common uses
This technique is useful when a raised line is required on a fabric which is too delicate for a heavy thread to be embroidered directly through the weave.
Embroidery Techniques
Related Stitches
References
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Mary Thomas, Jan Eaton, Mary Thomas’s Dictionary of Embroidery Stitches (Revised Edition) (1989) , p.13