Many years ago, there was a wonderful magazine called Weaver's -- and in it, an article by Ann Richards on using crepon yarns for collapse fabrics. I have had it in my files for more than 15 years and FINALLY I wove up some samples. The impetus was the annual sample exchange for the Collapse Weave Study Group in Complex Weavers.
The warp is 60/2 spun silk in black and natural, threaded alternately in a straight draw. The photo at top shows the fabric after washing, with a number of different wefts. A closer look, below.
Here's the fabric on the loom, showing horizontal stripes woven alternately in 60/2 spun silk in natural and 30/1 wool in a Z twist.
And then off the loom, before washing.
Here's what the same fabric looks like, close up, after washing in lukewarm water with a bit of Orvus paste.
And here are two other samples. Below, I have alternated weft stripes of black gossamer-weight silk crepe from Habu with 60/2 spun silk in black. The crepe draws in more than any other energized yarn I have used, so this is a very elastic fabric when you stretch it horizontally.
Finally, a softer collapse fabric, as the weft is just one yarn: 30/1 wool in S overtwist (natural color).
Threading 1,456 ends on the loom at a sett of 32 epi amounted to some 45 1/2 inches in width, which collapsed to roughly 30 inches in width after washing. The length didn't change much, from around 45 inches long to 41 inches after washing. Lots of weaving for a shrinkage of 33%, but it was so worth it!