This is source of frustration for me: wonderful light-colored fabrics where you can see occasional dark lines. And the lines are from a single strand of dark fiber twisted around the light cloths on a single thread, which is then woven into the fabric.
By now you can tell that I'm nearsighted! Still... the lines really stick out. If you were doing patchwork you could cut and work around it. But if you're using the fabric for borders or backing it's a real problem.
Has anyone else run across this? Did you find that there were particular brands where you found this more often?
I'll start: Springs Industries Quilters Only solids - white - which often has tiny RED fibers in it. I wouldn't buy this brand in light colors, and have switched to Kona Cotton instead. I never have a problem with their white!