Polyester has learned to shimmer. Here are the senses and small tests that still separate true silk from its clever imitations — and why the difference is felt first against skin.
Imitation silk has grown alarmingly good. The best polyester satins now mimic the drape and the sheen so well that a photograph can no longer be trusted, and the price tags have learned to lie convincingly too. But the imposters give themselves away to the senses — and nowhere faster than in lingerie, where the cloth spends the whole night against skin and has no styling to hide behind. Here is how a fabric is interrogated on the atelier table. No laboratory required.
First, the warmth
This is the test we trust above all others. Take the cloth in a closed palm and hold it for a slow count of thirty. Real silk is a protein fibre — kin, in a sense, to your own skin — so it warms quickly to body temperature and stays warm, with no clamminess. Polyester is plastic. It resists warming, holds a faint coolness, and the moment you open your hand it loses what little heat it took. This is the whole reason a real silk slip is comfortable in a Bangkok August and a polyester one is not: silk takes your temperature and then leaves you alone, while a synthetic sits on the skin like weather that will not pass.
Then, the light
Tilt the fabric slowly under a single light source and watch the colour. True silk is dichromatic: its triangular fibres refract light so that the surface shifts hue as the angle changes — a champagne reads gold, then ivory, then almost pink. Polyester shines, but it shines the same flat colour from every angle, a white glare laid over the dye. This matters on a body, which is not flat. Real silk moving across the hip gives you three tones in a single step; the imitation gives you one hard highlight that reads, unmistakably, as cheap in any light warmer than daylight.
“Synthetics shine at you. Silk shines through you. Once you have felt the difference against your own skin you cannot unfeel it.”
GINA HF — Bangkok
The small tests
- The scrunch. Crush a section in your fist and release it. Silk springs back almost smooth with only soft, organic wrinkles. Polyester either refuses to wrinkle at all — suspiciously crisp — or holds hard, sharp creases that will still be there in the morning.
- The sound. Rub two layers together near your ear. Real silk produces a faint, dry crepe: the famous scroop. Synthetics are mostly silent, or make a slick, squeaky sound that you will also hear under a dress all evening.
- The ring test. Draw a wide piece through a ring on your finger. Fine real silk slips through effortlessly and re-forms; many synthetics snag or bunch.
- The static. Run the cloth once against dry skin. Polyester charges and clings; silk, being protein and naturally moisture-regulating, stays quiet. A slip that rides up your thighs by the second hour is telling you exactly what it is made of.
- The price and the momme. Genuine silk is sold by weight; a luxury price with no stated momme and a featherlight hand is the oldest tell of all.
The burn test, used with care
The most definitive test is reserved for a single thread pulled from a seam allowance or a swatch — never a finished garment. Touch a flame to it. Real silk burns slowly, curls away from the flame, self-extinguishes, and leaves a brittle black ash that crushes to powder between your fingers, smelling distinctly of burnt hair or feathers: the signature of protein. Polyester does the opposite. It melts and shrinks toward the flame, drips, and hardens into a shiny black bead that will not crush, smelling of chemicals.
The blends that complicate everything
Modern lingerie is rarely one fibre. A silk knicker will have an elastane content in its band, a silk-covered cup will sit on a nylon mesh, and a bias slip may be edged in a nylon-blend Chantilly. None of that is dishonesty; elastane is the only thing that makes a band recover, and a pure silk lace would collapse under a season of wear. What you are testing is the ground cloth — the panel that touches you. Read the composition line by component, not as a single percentage, and be suspicious of any label that gives you one number for a garment made of four fabrics.
You will rarely need the flame. The warmth in the palm and the colour-shift in the light settle most questions in seconds. Trust your hands; they were judging silk long before there was anything to imitate it.
