Taffeta is very similar to dupioni in weight and structure. The fabric is crisp and a bit weighty and holds its shape very well. However, the major difference between these two finishes is in the appearance and feel of the fabric.
While dupioni appears textured, taffeta is very smooth and more tightly woven. Taffeta’s sheen will depend very much on the lighting. In dim or natural lighting, the material can appear almost matte, but in bright or studio lighting (like your photographer may use) the fabric can come off quite shiny.
It is versatile enough to work for day or night weddings, but does tend to look more formal.