Fortuny, Accordion, Sunburst: How Three Pleating Techniques Shape a Couture Garment

Not all pleats are the same craft. In haute couture, three techniques dominate the conversation: Mariano Fortuny's irregular silk plissé, the uniform accordion pleat, and the radiating sunburst pleat. Each is made differently, and each produces a distinct effect on a garment's structure, volume, and movement. Understanding how they work is the difference between seeing "a pleated dress" and recognizing a deliberate engineering choice in cloth.

Mariano Fortuny's Revolutionary Plissé: The Delphos Gown

Plissé is an ancient method—Fortuny's own account traces it back to Ancient Egypt—but it was Mariano Fortuny who, in the early 1900s, revolutionized it and consecrated it as a synonym of elegance, luxury, and sensuality. His plissé was obtained through a long manual process in which the fabric is folded back on itself, and the pleat, by its very definition, allows freedom and elasticity to both the fabric and the wearer.

How exactly did he do it? The honest answer is that no one outside the workshop fully knows. It is widely believed that such pleats could only be achieved when the garment was wet—quite possibly submerged under water—quickly followed by the application of heat to ensure the pleats kept their form. The technique sounds almost disarmingly simple; the results were anything but. Many Delphos gowns over sixty years old still maintain firm, flexible pleats today.

The Delphos gown, made of fine silk, is the technique's masterpiece. The silk was dipped many times to enrich the color from a neutral base, so that it changed tone according to light and the movement of the fabric. As the Metropolitan Museum's file on the dress puts it, the Delphos "exemplifies Fortuny's ability to transform something historical into a totally modern garment." The pleat invites the fabric to cling to the body's natural shape—movement and light, embodied in a fold.

Accordion Pleats: Uniformity and Fluidity

The accordion pleat is the workhorse of the family: symmetrical folds, each side of the pleat the same length, resembling the bellows of the instrument it is named for. According to the craft resource Made/in, accordion pleats are among the most common pleating styles, alongside side pleats and box pleats (in a side pleat, one side is shorter than the other so the pleat folds flat to one side).

Its construction can be done by hand or by machine. Machine pleating, as the New York Embroidery Studio explains, runs fabric through heated machines that shape it in the desired way—though this method is slightly less flexible than other forms, since it can only complete accordion, side, and sunburst type pleating.

Aesthetically, uniformity is the point. Because every fold is identical, the fabric gains consistent volume and a rhythmic texture that expands and contracts with the wearer's motion. Where Fortuny's plissé clings, the accordion pleat breathes in and out like its namesake, adding drama through regular, mechanical repetition rather than organic irregularity.

Sunburst Pleats: Radiating Drama and Volume

The sunburst pleat abandons parallel lines altogether. Instead of uniform folds running edge to edge, the pleats radiate outward from a central point—typically narrow at the waist and widening toward the hem. The result is a fan-like, dynamic effect that adds dramatic flair and movement, particularly to skirts and dresses.

The technical trick lies in the mold. One form of heat-pressing, known as cardboard pleating, uses pre-pleated cardboard molds to shape the fabric; for a sunburst, the mold is tapered so that the pleat width increases gradually from its origin point outward. This is what distinguishes it structurally from the accordion pleat: the same heat-setting principle, but applied through a geometry that transforms a cylinder of folds into a cone of radiating light and shadow.

Fabric's Role: Permanence in Polyester vs. Delicate Natural Fibers

Why do some pleats survive decades while others flatten at the first sign of rain? The answer is largely chemical. Today, the material best suited to making perfectly symmetrical pleats is pure polyester, because the creases remain intact even after washing—a permanent effect. Heat-pressing, in fact, only lasts on polyester; for fabrics that do not comply with heat-pressing, chemical pleating is used instead.

Fortuny's silk, by contrast, belonged to a more delicate tradition. Natural fibers cannot be heat-set into permanence the way synthetics can, which is why his wet-then-heat process—and the careful handling it implies—mattered so much. That his gowns still hold their pleats after more than sixty years is a testament to the method, not the material's inherent stability. Haute couture brands today often experiment with mixed fabrics precisely to negotiate between these two worlds: the drape and luminosity of natural fibers, and the durability of the synthetic set.

Comparative Typology of Haute Couture Pleating Techniques

The three techniques can be distinguished at a glance by asking three questions: how was it made, what does it do on the body, and what does it trace back to?

Read side by side, the table shows why a designer chooses one over another: Fortuny's plissé for a clinging, body-tracing line; the accordion for even, breathing volume; the sunburst for directional drama that widens as it falls.

Mastering Movement: The Impact of Pleating on Garment Design

What unites these techniques is that none of them is merely decorative. Pleating is a structural decision: it determines where a garment holds volume, where it collapses, and how it behaves when the wearer moves. Fortuny understood this a century ago—it was the sense of movement and light embodied by the pleat that resonated with him, and his workshops still make the plissé manually today, with no technology or "trick," only the accumulated experience of a tradition.

The accordion and sunburst pleats extend the same logic through industrial means, trading the hand's irregularity for geometric precision. Whether the pleat is set by a submerged silk gown or a heated machine fed with polyester, the question the designer answers is identical: what should this fabric do when the body inside it moves?

Appreciating the Craft: Identifying Pleating's Impact

Readers should now be able to identify and distinguish between Fortuny's plissé, accordion, and sunburst pleats, recognizing how each technique contributes uniquely to a garment's structure, volume, and movement. The measurable indicator of that understanding is simple: the reader can articulate the distinct visual and kinetic effects of each pleat type when observing haute couture garments—irregular and body-clinging for the plissé, uniform and bellows-like for the accordion, radiating and hem-widening for the sunburst. The next time a pleated gown crosses a runway or a museum case, the folds themselves will tell you which craft, and which century of ingenuity, made them.

Sources

• Fortuny's plissé: characteristics of the most famous pleats in the world
• Fabric Pleating Techniques in Fashion Design — New York Embroidery Studio — NYE
• Fortuny’s Pleats – Pushing the boundaries - Fortuny