Introduction to silk
It has been said that feeling the draping of silk across the skin is as close to heaven as one can get. Seriously, I took that quote verbatim from a source. Silk has excellent drapability, a characteristic shine, and is extremely soft due to the fineness of its fibers. Silk is made from silkworms, which are actually caterpillars, not worms. They are fed leaves until they are ready to form cocoons. They form their cocoons by spitting out silk to form little silk cocoons. These cocoons are unspun to harvest the silk thread created -- one cocoon forms one single thread, sometimes over a mile in length! It can take over 2500 silkworms to produce one pound of silk (remember that silk is quite light, though), but this meticulous process is why silk is often expensive and rare.
Brief history of silk
Silk has a fascinating history and was an important commodity for China for thousands of years -- for perspective, the Romans loved it so much that the Senate banned men from wearing it due to economic concerns -- too much wealth was leaving the country in exchange for silk. The process of harvesting silk from silkworms was discovered in Ancient China 5000 years ago by the wife of a Chinese Emperor, and this process remained a well-kept secret. Revealing the process or taking silkworms out of the country was illegal -- punishable by death! While China owned the silk monopoly for several thousand years, the secret was eventually leaked. Chinese migrants brought silk production to Korea around 200 BC, and later two monks smuggled silkworms eggs to Istanbul which allowed production to expand in Europe. Forget narcotics, people were smuggling silkworms. This tells you something about how great this material can be.
How silk is commonly used
Silk is unique in that it is used much more commonly in women's fashion than men's -- the same cannot be said of any other material. For women, silk can commonly be found in blouses, lingerie, scarves, and more traditionally in leggings. For men, it is more likely to be found in ties, pocket squares, suit linings, and underwear. Silk has also long been used by hunters as long underwear, because of its insulating properties.
Highlights and Strengths
This is not usually a category that gets scored in this series, but in this case it's a must. Silk is the market leader in lustre -- silk reflects light from most sides, creating a beautiful shine. Note that certain types of silk may appear to shine more than others. For example, chiffon silk is quite sheer, or see-through, so because more light travels through the fabric, there is less light that is reflected. Chiffon silk can still have a glow, but it is more subtle than for example, charmeuse silk. (Seriously, I dove so much into different types of silk that I'm considering making a guide just for the different types of silk).
When worn next to the skin, silk collects odour and sweat stains with relative ease. It is also absorbs deodorant and collect deodorant stains. Being a delicate fabric, cleaning is difficult to begin with, so these characteristics make it even higher maintenance. This is in fact such an issue with silk that some women choose to wear clinical strength deodorant to reduce perspiration and eliminate the potential for stains.
The short version is that silk is breathable in that it allows moisture vapour to be transmitted through the material. However, especially if you're wearing silk next-to-skin, don't be swayed into thinking it is a good summer material as some suggest. Silk is a better insulator than a summer material.
In general, silk is less breathable than suggested, and a better insulator than given credit for. As with any fabric, the breathability can depend largely on the weave of the specific fabric -- denser weaves will better retain heat, and thinner weaves will be more breathable, so wear your silk garments in accordance (i.e. wear thicker silk when it's cold, thinner silk when it's warm). In general, I do not rate silk as highly breathable. If you tend to get sweaty in the summer season, you may want to consider avoiding silk entirely. If you do wish to wear it anyway, consider a more relaxed and loose fit to allow for more airflow, and save the slimmer fits for the colder months. In summary, silk as a material is more on the insulating side, so keep it thin and loose if you want to wear it in warmer climates, and avoid it entirely if you sweat excessively.
One misconception about silk, commonly spider silk, is that it is "stronger than steel". This is enormously misleading. Some versions silk have a tensile strength that is higher than that of steel, meaning the fibers can withstand more stress before breaking. But this is only one category of measurement and it is irrelevant for fashion purposes. For example, silk is much more likely than steel to deform elastically when force is applied -- there's a reason we don't see silk in infrastructure like we do with steel despite having a "higher tensile strength".
Nonetheless, a silk garment is a high quality garment that should last if well taken care of. It is strong and resistant to ripping. It is resistant to abrasion and pilling. If you've wondered why silk stockings run, it's because they're manufactured extremely thin for appearing sheer (see-through) and additional comfort, creating the feeling of a second skin.
Silk fibers are elastic in that they can stretch 14-20% before fibers break. While silk does generally feel a little stretchy, the 14-20% stretch measurement does not necessarily mean silk will feel super stretchy when you wear it. It just means it can be stretched significantly before breaking. If you want silk with more of a stretchy feel, look for silk blended with lycra, spandex, or elastane.
Silk wicks moisture from your skin very quickly. Unfortunately, this a weakness and not a strength with silk as the garments are so thin it will immediately show. Also, perspiration that is absorbed can yellow the fabrics. Silk will also absorb standard deodorant, allowing it to stain the garment. Many who wear silk will wear clinical strength deodorant, usually a liquid that dries quickly on your skin rather than leaving excessive residue for a garment to absorb.
Weight and Packability: 10/10.
Silk is as light and thin as it gets.
Silk is generally resistant to wrinkling. To be specific, high quality silk and thicker silk will be fairly resistant to wrinkling. However, thinner and poorer quality silk will wrinkle like crazy. Your mileage may vary quite a bit here! If you're buying in store, crumpled up the garment and see if it springs back or wrinkles up. If you're buying the item online, check the reviews to check for any comments about wrinkling.
As close to heaven as one can get. This is one of silk's ultimate features: it is incredibly soft. Best on the market.
Ease of care: 2/10.
Silk is high maintenance -- most silk items must be dry-cleaned. It is quick to absorb sweat, which weakens and yellows the fabric, generally meaning that any silk worn next to the skin should be washed or cleaned after every wear. This can be a hassle if the garment requires dry-cleaning. Some silk garments are washer-safe, but silk is 20% weaker when wet, therefore this must be done with care.
Water Retention: 4/10.
Some misinformation on this topic, with sources rating the absorbency of silk between 10-30% of its weight in water, which is a huge range. For practical purposes, consider that silk is extremely light to begin with, so even if it absorbed as high as 30% of its weight in water, this is not going be enough to wick all your sweat on a sweaty day. Regardless, the wicking features are not something you really want with silk because it is a bit slower to dry and stains easily so the stains end up sticking around all day. This also means there will be some chafing due to the sweat that isn't absorbed once it's saturated. Avoid sweating if you'll be wearing silk next to skin!
Drying Speed: 4/10.
Silk absorbs quickly but does not dry quickly. Silk can get uncomfortable when wet and in a hotter climate, could stay wet most of the day.
These are the properties of silk, a silk primer.