How to Identify Vintage Fabrics and Fibres

Last reviewed 2026-10-04 by the AntiqueCostume editorial team · Sources · How we research

Knowing what a vintage garment is made of tells you two things: whether it is old enough to be what the seller says, and how to clean and store it. A careful burn test on a loose thread will sort most fibres into three families (protein, plant-based cellulose, or melt-prone synthetics), and a fibre introduction timeline then tells you the earliest the garment could have been made. For exact identification, especially of blends, museum conservators use a microscope; the burn test is a quick home check, not proof.

Quick answer

Protein fibres (wool, silk, hair) curl away from the flame, smell of burning hair and leave a crushable ash.
Cellulose fibres (cotton, linen, rayon) catch easily, smell of burning paper and leave soft, flaky ash.
Acetate smells sharply of vinegar and melts; synthetics such as nylon, polyester and acrylic melt and leave a hard bead.
Use the result to rule out dates: no nylon before 1939, no polyester in US clothing before 1953, no spandex before about 1960.
Burn tests cannot reliably identify blends, and they are destructive. Never cut into a garment to get a sample.

Before you test: take a sample safely

The American Institute for Conservation's textile identification guidance treats fibre identification as destructive testing, because the sample cannot be put back, and notes that a burn test needs a sample at least 1 cm long. For a garment you might sell or keep:

Use a loose thread from an inside seam allowance, a frayed edge, or a spare piece in a hem or seam that is already detached.
Test each component separately: face fabric, lining and sewing thread can all be different fibres.
If there is no loose material, skip the burn test and rely on labels, feel and the timeline below.

Equipment: tweezers, a candle or lighter (matches add their own smell), a non-flammable dish, and water to hand. Work away from the garment, in good ventilation, and keep children and pets away.

How to run a burn test

The conservation procedure is simple:

Hold the sample in tweezers and move it slowly toward the flame. Watch how it reacts as it approaches: does it shrink away, melt, or ignite before touching the flame?
Put it in the flame and remove it. Does it keep burning, melt and drip, or go out on its own?
Note the smell.
Let the end cool and examine the residue. Is there ash or a bead? Touch it: is it soft and crushable, or hard?
Compare your result with a burn of a known fibre if you have one. Smell descriptions are subjective.

What the results mean

Fibre family	Near the flame	In the flame	Smell	Residue
Protein: wool, silk, hair	Curls away	Burns slowly, often self-extinguishes	Burning hair	Dark, crushable ash or soft bead
Cellulose: cotton, linen, rayon (viscose)	Ignites quickly	Burns readily, may glow	Burning paper, leaves or wood	Soft, flaky grey or black ash
Acetate	Melts	Melts and burns	Sharp vinegar	Hard, dark bead
Synthetics: nylon, polyester, acrylic	Shrinks and melts	Melts, may drip	Chemical or plastic-like	Hard, shiny bead that will not crush

Practical points:

Rayon burns like cotton. A burn test cannot tell them apart. Feel and drape help: regular viscose rayon has low durability and appearance retention, especially when wet, so handle it gently if you suspect it.
Silk versus wool. Both smell of hair. Silk is usually a fine continuous filament with a high sheen; wool is crimped and springy.
Blends confuse the result. Conservation guidance is blunt that burn testing only separates protein, cellulose and thermoplastic types and cannot identify blends. If you see both charring and melting, assume a blend.
Finishes and dyes can change how a fabric burns. Treat surprising results with caution.

Other non-destructive clues

Labels. Fibre-content labels became common in the US after mid-century labelling laws; see How to Date Vintage Clothing by the Label and Dating Vintage Clothing by the Care Label. Trade names are a dating clue in themselves: Orlon, Acrilan and Creslan (acrylic), Dacron and Terylene (polyester), Celanese, Acele and Estron (acetate), Dynel (modacrylic), Lycra (spandex), Bemberg (cupro).
Static and pilling. Synthetics tend to hold static, and polyester pills are hard to remove.
Hand and drape. Linen creases sharply and holds the crease. Compare an unknown fabric with known examples you own.
A warning about acetate. Acetate fibre is made by dissolving cellulose acetate in acetone. Nail polish remover and some solvents can therefore damage it, which matters for cleaning; see Removing Stains and Odours from Vintage Clothing.

Fibre timeline: what could exist when

Use this to test a date claim. If the fibre was not available yet, the garment, or that part of it, is later than claimed.

Fibre	Key dates	Notes
Rayon (viscose)	First commercial production by Courtaulds in England, 1905; US production by American Viscose from 1910	Earlier "artificial silks" existed (Chardonnet silk from 1884), but they are very rare in surviving clothing
Cupro (Bemberg rayon)	Cuprammonium process developed by Bemberg in Germany, 1890	Often used for linings
Acetate	First spun commercially in the US in 1924 (Celanese); made commercially in England after the First World War	The FTC separated acetate from rayon as a fibre category in 1953
Nylon	DuPont announced it in 1938; commercial production began December 1939; stockings went on national sale May 15, 1940	Diverted to war use (parachutes) during the Second World War
Modacrylic	Developed in 1949 (Dynel)	Used for wigs and fake fur
Acrylic	Developed by DuPont in 1941, introduced to the public in the early 1950s as Orlon	Common in 1950s sweaters
Polyester	Patented in Britain in 1941; commercially introduced in the US in 1953 (Dacron) and Britain in 1955 (Terylene)	Ubiquitous by the 1960s and 1970s
Spandex	Invented at DuPont in the late 1950s (sources give 1958 or 1959); full-scale production as Lycra by early 1961	Elastane in Europe

Natural fibres (cotton, linen, wool, silk) do not date a garment on their own, but a natural fibre in an item claimed to be a 1970s "polyester classic" may suggest a different maker or market.

Putting the result to work

Dating: a 1920s dress with polyester thread throughout has been remade or is a later piece. A "1940s" sweater in Orlon acrylic is probably early 1950s or later. See Reproduction vs Antique Clothing: How to Tell.
Authentication: a designer piece in a fibre the house did not use in that period deserves scrutiny; see How to Spot Fake Designer Labels on Vintage Clothing.
Value: silk, fine wool and good linen generally command more than equivalent synthetics, but well-preserved period synthetics, such as printed 1970s polyester, have their own buyers. Condition matters more than fibre; see Vintage Clothing Condition Grading: Mint to Fair and What Each Costs.
Care: fibre decides how you clean and store it. See How to Clean Vintage Clothing Safely and How to Store Vintage Clothing Long Term.

If you need a definite answer, for example for a museum donation or a high-value sale, a textile conservator or a university textile lab can identify fibres under a microscope from a tiny sample. The Ohio State University's Fiber Reference Image Library (FRIL) shows what those microscope views look like.

Scanning electron microscope image of a fine Merino wool fibre above a thicker human hair — A superfine Merino wool fibre (top) and a human hair under a scanning electron microscope, the kind of view conservators use for exact fibre identification.
Wool, a protein fibre: in a burn test it curls away from the flame and smells of burning hair
Human hair, also a protein fibre: wool, silk and hair all burn the same way
Magnification and scale bar (x1.0k, 50 um): fibre detail needs a microscope, not a flame
Photo: CSIRO, ScienceImage 8115 (via Wikimedia Commons), CC BY 3.0. Shown for illustration; we have not handled this garment.

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