There are a few ways to determine fibre content in a fabric. The simplest is obviously to check the tag on your dress or the end of the fabric bolt before you buy your material, but if those options aren’t available to you, all is not lost. You can still figure out what you have on your hands to some reasonable degree.
The Hand Test
A hand test is just what it sounds like: how does the fabric feel in your hands?
What does it do when you scrunch it up, or tug on the corners?
In reference to fabric, hand is a way of saying “the way fabric feels or behaves when handled”. This test is a bit tricky for synthetic fabrics like polyester, because they’re specifically designed to mimic natural fibres. The goal is to get a rough idea of what the fabric might be, and then confirm it with a burn test, or by comparing to a written record you might have, such as store receipts.
A few common things to keep in mind is that cotton will not immediately take wrinkles when you scrunch it up, but generally won’t try to return to its previous position, and will form creases in those spots over time. Rayon and polyester will mimic whatever fabric the weave has been used to imitate, are less likely to take wrinkles on than their natural counterparts, but unlike natural fibres, they don’t retain body heat as well. Because it is an artificially processed material made from plant cellulose, rayon will warm to your touch, but quickly cool when left alone. Polyester, however, generally won’t hold onto your body warmth at all, and instead will insulate you due to its lack of breathability.
For more examples of how hand affects fabric determination, please check the resources section!
Burn Test
This test isn’t for the faint of heart, and is generally something better done on fabric you’re using to sew, rather than a dress you’ve already bought.
To conduct a burn test, you need a few strands of fibre or a small section of fabric from the material you want to test. If you absolutely have to test a garment, try to snip loose threads from the yarn of the fabric, preferably from somewhere that isn’t highly visible. You will also need a fire-proof container such as a pie plate, sink, or metal bowl, some tweezers or tongs to hold your sample, and a lighter, candle, or match. Tea lights are a good option, since they’re easily set aside.
Everything you'll need to conduct a burn test on a piece of fabric. |
To start your test, hold your sample in your tweezers or tongs (please do not do this with your bare fingers), and carefully apply your flame to one corner. As soon as you see the flame take, remove the flame source from the sample, and watch what happens. If you remove your sample from the flame, you risk prematurely extinguishing the sample or changing its behaviour while it burns. So generally, I recommend removing the source of the fire rather than the sample.
A synthetic material will generally melt, and extinguish itself quickly. It leaves behind little ash, and the edges of the material will ball up into hard, plastic-like lumps where the flame burned. Acrylic and some polyester will also give off a faintly petrol/gasoline-like aroma.
A natural material will behave according to its fibre type: cotton will continued to burn and will turn to ash similar to, and smell similarly to burnt grass or leaves; wool will extinguish once the flame is removed, and generally smells like burnt hair; silk will generally extinguish immediately, but if it continues to burn, it will retreat or crinkle back from the flame, produces black, sooty ash, and smells a bit like burnt hair or meat.
You can test known fibres to compare them to your unknown sample, or check YouTube for burn tests other people have conducted to see examples of what to expect.
Examining the Weave
This part of the process is mostly down to practice, and research. Different weave patterns look pretty distinct once you know what to look for, but the differences between some varieties can be nit-picky and difficult to determine at times. Sometimes, materials just look too close to call, and you should use your best judgement based on the factors you know are completely certain.
The best method to use in identifying a fabric by sight is simple comparison. I’ve included a few guides to different woven fabric types in the resources section for you to check out, and they include clear, close-up pictures of different weave patterns as examples. You can also use the examples provided in the previous fabric guides, or search through Lolibrary in the case of existing garments.