The photo above shows some collapse-weave fabric, just taken off the loom and washed, that clearly has two distinct textures. If you look closely, the top 1/3 of the piece is slightly more dense and darker in color, with an emphasis on the dark stripes. The section at the bottom 2/3 of the photo features the blue/green stripes and is slightly looser and broader.
Why? It took me a while to figure this out. Simply put, I changed the weft -- and thought that there would be little difference in the outcome. The warp is hand-painted 60/2 silk and the weft is a super-fine overtwist wool. The difference: the weft used at the top of the photo was a 2-ply overtwist wool from Habu. The weft at the bottom of the photo was a Z-twist wool from the Handweaver's Studio and Gallery in London. BIG difference between the two and I intend to exploit this when I make the garment.
Here are a few more views:
The fabric when it's dry
Closeup of the same
And here's the back
And so I learned, from a process of trial and error (emphasis on error), that yarns of the same color, fiber, and grist can behave very differently, depending on whether they're plied, singles, Z twist, or S twist. As a spinner, I know this. As a weaver, it took me a while to know this!
Here's one more view of the fabric, still drying. I like to call it "Colorado Creek Bed," remembering the gorgeous scenery in Colorado, where we just spent our Christmas holiday with my daughter and her fiance.