Are shantung and dupioni the same fabric?

No, though they are close cousins and the terms are sometimes used loosely. Both are plain-weave slub silks, but dupioni is reeled specifically from double cocoons, giving heavier and more irregular slubs and a stiffer, shinier cloth than shantung.

What causes the slubs?

In dupioni, two silkworms spin a single shared cocoon, and reeling that joined cocoon produces a thick, uneven thread whose lumps become the slubs. In shantung, the slubs come from natural irregularities in the silk yarn rather than from doubled cocoons.

Which is better for a wedding dress?

Dupioni is the more common bridal choice because its stiffness and bright sheen hold structured shapes well. Shantung is chosen when a softer, finer drape is wanted while keeping a crisp silk hand.

Side by side

Shantung vs Dupioni

Shantung and dupioni are both crisp, lustrous silks defined by slubs, the irregular thick spots in the yarn that catch the light. The difference is degree and origin. Shantung is the smoother of the two, with fine, occasional slubs running across the weave. Dupioni is reeled from double cocoons spun side by side, so its weft is heavier and more irregular, giving a coarser, more pronounced slub and a stiffer, shinier cloth.

Shantung

No. 079

plain weave, slubbed weft · first documented 1800s

Dupioni

No. 093

plain weave, slubbed · first documented 1900s

The differences

Aspect	Shantung	Dupioni
Source of the slub	Irregularities in the silk yarn itself, traditionally from wild or tussar-type silk.	Two silkworms spinning a single joined cocoon (doupion), reeled together into one thick, uneven thread.
Texture	Fine, fairly even slubs; a relatively smooth crisp hand.	Heavier, more frequent, more irregular slubs; a rougher, more textured surface.
Body	Crisp but lighter and more fluid.	Stiffer, with more body and a brighter sheen.
Best for	Shirts, dresses, lighter tailoring.	Structured eveningwear, bridal gowns, drapery, anything that benefits from stand-away body.

Which to choose

Both are slubbed silks; dupioni is the more dramatic of the two. If the slubs are heavy, frequent, and the cloth stands away from the body with a hard shine, it is dupioni. If the surface is finer and the hand softer while still crisp, it is shantung.

Common questions

Are shantung and dupioni the same fabric?: No, though they are close cousins and the terms are sometimes used loosely. Both are plain-weave slub silks, but dupioni is reeled specifically from double cocoons, giving heavier and more irregular slubs and a stiffer, shinier cloth than shantung.
What causes the slubs?: In dupioni, two silkworms spin a single shared cocoon, and reeling that joined cocoon produces a thick, uneven thread whose lumps become the slubs. In shantung, the slubs come from natural irregularities in the silk yarn rather than from doubled cocoons.
Which is better for a wedding dress?: Dupioni is the more common bridal choice because its stiffness and bright sheen hold structured shapes well. Shantung is chosen when a softer, finer drape is wanted while keeping a crisp silk hand.

Full entry: Shantung Full entry: Dupioni

Sources & References

1.Shantung (fabric), Wikipedia
2.Crepe (textile), Wikipedia
3.Dupioni, Wikipedia
4.dupioni, Wiktionary