Silk was one the primary fabrics utilized in period fashions during the 19th Century and early 20th Century and over the years, a lot of mystery and downright misinformation has grown in regard to this beautiful and useful fabric. One question that always seems to arise is: “What is Dupioni silk?”
Contrary to popular belief, it’s NOT some sort of fancy Italian silk fabric that was developed for haute couture houses in Milan nor is it some sort of manufactured fiber along the lines of nylon or polyester. Really. 🙂
No, in reality Dupioni silk is nothing more than silk filament that’s produced when two silk worms spin their cocoon together (sometimes this is referred to as a “double cocoon”). When the silk filament is by reeling (“reeling” is the process of unwinding the raw silk filaments from the cocoon), the resulting filament, is irregular and so is the spun yarn; ultimately, this irregularity shows up on the silk as irregular “slubs”.
Side by side comparison of regular silk yarn on the left vs Dupioni silk yarn on the right.
OK, that all sounds good but there’s still more to keep in mind! As part of the weaving process that converts silk yarns into silk fabric, the uneven/irregular Dupioni yarns are used as fill yarn while thinner, regular straight silk yarns are used for warp yarn. The Dupioni yarns are too weak to be used for the warp since the warp yarns are under constant tension during the weaving process. When looking at a piece of Dupioni fabric, you can easily tell what direction is the grain because the grain will always be running perpendicular to the slubs. Another tip-off is that warp yarns tend to be thinner and run parallel to each.
Below is a swatch of Dupioni fabric where the warp yarns are actually salmon/pink. Dupioni is a  balanced plain weave (i.e., there are an equal amount of yarns interlaced one over the other) fabric but the actual Dupioni yarns are more thick, thus they are more apparent and dominate the color of the fabric. If you look closely, you can see a hint of the pink/salmon.
Here is a swatch of Dupioni fabric that’s been diagrammed. Note that the warp yarns travel from top to bottom while the fill yarns run from left to right. The grain would be running up and down while the selvage edge would be to the left and right. This may sound somewhat simplistic but it makes all the difference when sewing and you do not have a selvage edge that you can look at.
Diagram of plain weave fabric.
Below are a few samples of Dupioni silk fabric:
This is a good example where the slubs are visible.
Bolts of finished Dupioni silk fabric. Note that the selvage edges are on the bottom of these two bolts and that the slubs follow in a line towards the selvage. The grain would be running perpendicular.
OK, now you’re probably wondering how Dupioni silk is different than silk Shantung since both exhibit the characteristic slubs…well, not much (besides having been originally made in the province of Shantung in China) depending what you read. 🙂
From a visual perspective, there is not much of a real difference except that the slubs tend to be somewhat less prominent. Also, Dupioni is hand woven while Shantung is machine woven. Shantung also takes advantage of the fact that when initially reeled, raw silk filament tends to be somewhat irregular in texture and as such is directly used with little further processing. However, as with Dupioni, it’s only used as fill yarn while the warp yarns are more refined.
Dupioni take dying very well and is available in a wide variety of colors and effects. Often two different colors of warp and fill yarns are used and in some cases, different color yarns can be used in either the warp or fill. Â Also, Dupioni is wrinkle resistant.
At Lily Absinthe, we use quite a lot of Dupioni AND Shantung silk in our designs, either in part or in whole and it forms some of the basic fabrics we use. Below are just two examples:
Dupioni:
Here’s a recent commission made from a high quality pale blue Dupioni.
Shantung:
The front solid panel, the pleating, and the faux weskit front are made from silk Shantung. The stripped silk on the bodice is a silk taffeta and the ruffles in the rear of the skirt are a silk charmuese.