These blackout-lined silk panels were sun-damaged and the homeowner wanted to cut off the damaged part and re-hem the lead edge sides.
A few weeks ago I was experimenting with a way to hem drapery lead edges without pinholes of light coming through the blackout lining.
This was a perfect chance to practice and test my idea.
The return edge was undamaged and didn't need re-sewing, so I did the flashlight test (the only test that is definitive) on the original machine blindstitching, and the result was a lot of bright light coming through each stitch hole.
But on the lead edge, with my stitching method, there was zero light. Yes, there is a flashlight directly behind the stitches in this photo!- and I'll prove it, at the end of this post.
I used a blind-stitch variation: the same stitch I learned as a girl for hemming skirts. But for these panels, I made the stitches about 3/8" in from the edge instead of right at the edge as I first learned it.
First I folded two layers of blackout into the side hem along with the silk.
Holding the lead edge folded back, I started a stitch in the fold:
Then dipped down and about 1/8" over to take a stitch in the face/lining: