In the post about the floral 1940s dress, I mentioned that I preformed a burn test on some fabric to determine its fiber content. You may be wondering: what is a burn test, and how does it relate to fashion history?
How the fabric burns, its smell, and the ash it leaves behind are three sensory details that aid in identification of fiber content. Burn tests are a great way to test fabric that you want to know more about - especially if a visual test or a touch can't determine the content. Many synthetic fabrics that came about around or just before World War II look and feel like silk or cotton, but aren't.
Make no mistake - I don't advise this for all historic clothing. Once you get into the 1930s and later, the fiber content of many articles of clothing become more synthetic, which is where the issue comes in. Prior to that, most garments were made of cotton, linen, wool, or silk, and are fairly easy to determine just by look and touch.
After 1960, U.S. garments were required to include a tag with the fiber content and percentages of each, as well as the country of manufacture. So, the burn test is really only for clothing/fabric manufactured between 1940 and 1959. While there are some fabrics that predate this time period - acetate (1913) and rayon (1924), it wasn't until nylon was introduced to the US market in 1939, and polyester in 1941, that synthetic fibers began to replace organic fibers. Many of the natural fibers were diverted to use during the war, leaving different alternatives for clothing construction. The low cost of the man-made fibers also made it more desirable for the consumer.
And you may be thinking - why does all this matter? In terms of preservation and conservation, the type of enclosure, acid-free tissue, and treatment depends on the fiber content of the garment itself. For protein based fibers, such as silk and wool, you would use a different type of enclosure than the synthetic fibers. The rate of deterioration differs greatly between objects, and conservators are now finding that synthetic items are deteriorating at alarming rates, even when kept at the optimal conditions.
While I wish I had time to film various burn tests for you all, this in depth video from Sawyer Distinctive Fabrics showcases a number of fabric swatches, covering the color of the burn, the ash content, and the smoke content. Unfortunately, she doesn't cover the smell of each of the burns, which I'll include in a little chart below. Or, if you don't want to watch it, you can just skip ahead to the chart :)
This test works well if you sew and have long forgotten the fabric content of some yardage you purchased, or if you found some fabric at a yard sale or thrift store. Just like preserving fabric, some fabrics are better for projects than others!