Bemberg is a brand of Cupro, a regenerated cellulose fibre which is produced by using a closed loop system. Cupro is made from cotton lint which is a waste product from the manufacturing of cotton; it is therefore a semi-synthetic fabric which is natural and breathable.
The synthetic nature of this fabric is due to the many processes it goes through, using various chemical solutions to reach the point where the fabric can be woven. The end result is a cloth that is soft and silky.
Cupro fibres are naturally very fine, creating a densely woven breathable fabric.