The Heartbreak that is Weighted Silk

We have a number of fantastic volunteers at CHS for the summer, and I am lucky enough to have a few working with me up in the costume collection.  One of our volunteers, Jessi, is helping me with something I have wanted to do since I started here….catalogue and photograph all of our costumes that are currently housed in drawers as they are too fragile to hang.  I cannot take credit for the cataloguing as Jessi is taking care of that part, but removing and replacing the items in the drawers plus photography are all two-person endeavors.  Well, because of this…

Dress. 1907-1914. CHS Collection. 1996.175.0.

This beautiful, seafoam green, silk velvet gown is lined in silk.  But this is not the beautiful, high-quality silk of the 18th and early 19th centuries, it is weighted silk from the turn-of-the-century.

What is weighted silk, you might wonder.  Well, I’ll explain.  Silk comes from the cocoon of a silk worm and when the silk is processed so it can become silk thread (and later silk fabric) it is washed in order to de-gum it.  You see, when the silk comes out of the silk worm it is coated with a sticky substance, gum, that binds it to other strands of silk to form the cocoon.  The problem with de-gumming silk is that it lightens the weight of the silk.  So, when silk manufacturers would de-gum 10 pounds of silk they may only end up with 8 pounds in the end because 2 pounds of gum was removed.  Furthermore, since silk was sold by weight rather than by the yard, manufacturers felt they had the right to add back the lost weight into the fibers.  They did this with chemical salts such as tin or lead.

Shredded weighted silk lining.

But, silk has an aversion to these chemicals.  Over time the chemicals would eat away at the silk and weaken it to the point of breaking.  Some silk merchants would even add more than just the weight that was lost resulting in even weaker silk fibers.  This silk was often sold cheaply and shows up in dress linings, where less-weighted silk (thus “truer” silk of a higher quality) might be used for the outside of the dress leaving that portion in tact with less chemical decomposition.

Internal hem ruffle on weighted silk lining.

The most telling sign of weighted silk is a shredded effect that gives the appearance that a cat climbed inside the garment and had a frenzy!  The silk tears especially along seams or folds.  In the picture above, the pleated ruffle is actually split down many of the hard pleat creases.  In silk fabrics with less weighting you may notice just small, occasional splits in the fabric.

Weighted silk bodice lining.

Because extremely weighted silk was often the cheapest, it was usually used for garment linings.  The height of its popularity was around the turn of the century and many dresses that survive so extraordinarily on the outside from this period have increasingly fragile linings…thus forcing them to be stored flat rather than hanging.  Because the chemical reaction of weighted silk is unstoppable, these linings cannot be easily conserved.  There are typically two options: underline and overline the entire lining in order to encase the shredding silk; or remove and replace the entire lining.  In a dress like this one, where the lining is not integral to the structure of the dress in the skirt area, but is in the bodice (as you can see in the above photograph the lining holds the hook and eye closures, and the boning) the weighted silk lining would likely be removed and another lining made just for the bodice.  In such conservation cases, multiple photographs would document the lining both before and after conservation to show what was, and is now, there.

In the case of many of our dresses here at CHS, we choose to store the garments flat in order to prevent any unnecessary degradation.  Each garment coming out of the drawers will be carefully catalogued and photographed for documentary purposes.  Photographs of both the inside linings and of the outside (carefully dressed on a mannequin or flat on a hanger) will help us to see and study the garments without undue wear and tear.

The idea of cheap silk sounded so good at the time, but the sad truth is starting to come to light of the sacrifices made for affordable garment lining fabric.