Silk Notes
Our ultra-premium silk-lined masks are made with an outer layer of patterned cotton fabric, plus one or two layers of genuine silk lining (your choice). Any of the approximately 150 patterns we offer can be ordered with silk lining.
I (Theodore) was initially skeptical of silk as a lining for masks: what could possibly match the comfort of cotton against the skin? But it turns out silk is actually a wonderful material for this purpose. It feels, well, silky, and does not get clammy or sticky. It is an extremely finely woven material (silk fibers are far thinner than cotton), yet very easy to breathe through. (See this page on our Breathing Resistance Rating for more details on breathability.)
The silk we use is high-grade 19 momme mulberry silk charmeuse. Let me take apart that description for you.
“High-grade” means nothing, it’s pure marketing fluff.
“19 momme” refers to the weight/thickness of the silk. Momme units are the weight in pounds of 100 yards of 45” wide fabric. 19 momme is sturdy silk, typically used for quality silk bed sheets. It drapes and flows in a most satisfying way.
“Mulberry” means the silk worms are fed exclusively on the leaves of the white mulberry tree, which is their preferred natural food.
“Silk” means this is actually silk, not a synthetic imitation. The fibers come from the cocoons of the domestic silk moth, bombyx mori. (If it helps, people often eat the larvae as a snack after they are removed from their cocoons, so nothing goes to waste.)
“Charmeuse” means the silk fibers are woven in a satin pattern, in which the weft yarns run typically in a 3-over, 1-under pattern through the warp yarns (shown here with thick rope so you can see the pattern). Satin weave fabric has a smooth, satin-feeling side, and a rougher back side. Naturally we put the smooth side towards your face.
Satin Weave Smooth Side
Satin Weave Rough Side
Under the microscope you can see that the silk has the same weaving pattern, just much, much smaller (barely visible to the naked eye).
Silk in Satin Weave, Smooth Side
Silk in Satin Weave, Rough Side
A big difference between silk and cotton is that individual cotton fibers are only about an inch long, and are twisted together to form long threads. Individual silk fibers can be up to a kilometer long! But they are incredibly thin, around 10 microns in diameter. To make a thread thick enough to plausibly weave, dozens of individual silk fibers are run in parallel through each crossing point. Because the fibers are so long, there is no shedding over time.
Our silk is from Hangzhou, the ancient center of silk production in China where silk worm cultivation first started over 5000 years ago. (To put it another way, when the Great Pyramid of Giza was under construction in Egypt, people had already been weaving silk in Hangzhou for hundreds of years.) Chinese silk production today is the most advanced in the world, resulting in a consistent, high-quality white silk product.
How, you may ask, can we be sure this is genuine silk? Good synthetics are remarkably similar to the real thing, fooling even experts by sight and touch alone. Well, I’ve got you covered there, because I literally wrote the book on how to tell real silk from fake! Well, not the book, just a book, and actually it was just one chapter on fibers in a book about Molecules, and if you want to get technical, there’s really only one page about testing silk. But I did carefully calibrate my ability to distinguish real silk by testing a variety of synthetics against whole silk cocoons, which could not possibly be fake.
The test is to burn it. No other method short of laboratory chemical analysis is definitive, but burning instantly reveals the truth.
Silk does not sustain combustion without a source of flame, and it burns into a crumbly char. There is also a very distinctive smell, not unlike burning hair. Common synthetics (such as nylon, which can feel very much like silk) burn on their own, and melt into flaming drops that fall to the floor.
Our silk passes the flame test easily. I confirmed the 19 momme weight of the fabric with our analytic balance, and it is sourced through our trusted local partner in China, so I can stand behind the authenticity of this material 100%.
Burning silk
Burning Nylon
Working with silk is difficult (which accounts for most of the added cost of our silk-lined masks). It requires extra-fine sewing needles, and can be difficult to cut to a pattern, because it doesn’t hold its shape, being so…silky.
Fortunately, laser cutting silk works extraordinarily well (and is in fact a technique used in high fashion, where laser cutting is used to execute otherwise impossible lace patterns). In this video you can see our laser cutter making silk lining pieces.
A wonderfully useful property of laser-cut silk is that the heat of the laser fuses the ends of the fibers, effectively sealing the edge and preventing fraying. It also causes multiple layers cut together to stick to each other along the cut edge. We use this property to make sewing easier: we cut two layers at once, and then sew the center seam without separating them. This keeps the two halves in absolutely perfect alignment. After sewing, it’s easy to split and pull apart the layers.
However, this property also means that we have to cut only two layers at once, vs. the 8-16 layers of cotton fabric we typically cut in one go. Furthermore, cutting residue generated by the silk will contaminate the bottom side of the fabric if it’s resting directly on the honeycomb table. That means we have to lay a new sheet of paper (which gets cut up too) on the table for each sheet of silk we cut. All in all silk is a labor-intensive material for masks, but worth it.