— my opinion and experience – answering here since this is a question I get frequently — the best thing is to do a test of the thread in the context you are using it.
Choosing silk for embroidery – here are my hints –
Silk is either reeled or made from bits glued together. This is because it is either reeled off the cocoon or the cocoon is cut up to get the bug out. Most medieval silk is reeled. It makes a difference on the shine. Silk essence is rayon not silk – fyi.
Splendor is cut up. I find 1 in 6 cards is too much of a bitch to work with and toss it. BUT it is what I use for price, shine, and general ease of use for teaching.
Pearsalls is reeled. It is the main one I will use for fine blackwork due to the awesome shine with Au Ver Soie 100/3 as my backup since Pearsalls is hard to get in the US. I also use the 100/3 for my goldwork.
Au Ver Soie – reeled – Ovale is too thick for fine work but works well for motifs in the 2-3″ diameter range. Trame is lovely for fine work. Paris has a slight twist which makes it easier to work on detached buttonhole and stitches with lots of “rubbing” while working.
Subtelty is Rainbow Gallery equal to #12 pearl, Elegance is #8, Grandeur is #5 — these are heavily twisted but will take a lot of abuse/use and still have a lovely shine. Don’t think they are reeled.
Trebizond – reeled – 12 ply twisted. If you untwist it. Straighten and dampen with a cloth. You have awesome fine threads of silk. It is my go to when I need to do shading.
DeVere silk – reeled – from the UK – has a bit of twist to it but lovely to work with and super close in diameter to much of the historical silk embroidery used.
Here is an article I wrote a number of years ago about silk threads. Hope this helps. http://www.bayrose.org/AandS/handouts/Silk_Article-1.pdf
Sabrina de la Bere