@effinbirds Rayon is what I'm accustomed to seeing. It's a much nicer fiber, but probably costs more, raising the prices. I don't know if that is an option with your sources. Silk would be outstanding and stupid expensive. I only mention it for completeness.
@herveus if you can send me some close-up photos of fine print on either, I'll try to figure out what's holding back our manufacturer from achieving the same results. The tests I saw were just not acceptable.