I love silk fibers and use them often, much to my wallet's dismay :>) ! Belle Soie is wonderful, but if you want an inexpensive silk, I recommend Vicki Clayton's. She has some beautiful colors, the quality is great, and you can't beat the price.
Very nice post. Wonderful photos...I just want to grab those flosses! I've only ever used cotton flosses...DMC, Weeks Dye Works and what comes in kits but I'd love to try these beautiful threads!
If you are worried about colour fastness, make a few stitches on a piece of scrap white fabric. Moisten a paper tissue and dab the stitches. If any colour comes off onto the tissue, you have your answer! Either wash the thread and risk losing the original shade, or make sure your hands and work area are pristine throughout your project.