Here at The Vintage Optical Shop we get to see a nice sampling of the frames made 50-150 years ago. We can often tell by the quantities of the different vintage eyeglass frames we get which were the most popular in their prospective era and which were more rare. We can also tell which vintage frames lasted until today and what types would easily break and not make the 10 year mark, let alone last for 100 years.
One of the more beautiful styles of antique eyeglasses are the tortoiseshell eyeglasses or plastic (faux tortoiseshell) vintage eyeglass frames. They were generally round, oval or ovid in shape and have a classic and timeless look, and are one of the more popular styles we sell. But there are not too many of them around today.
To understand the reasons behind this we need to go back a little into the history of vintage eyeglasses and their evolution and development until today.
In the early days antique eyeglass frames were often made of Wood, Horn, and bone, depending on the availability of material and what worked best with the technology available in that era. During the late 1700’s early 1800’s they started making eyeglasses out of different types of metals and aluminum. Nickel silver, iron, bronze, aluminum alloy, steel and gray as well as the precious metals, silver and gold.
In the early 20th century they started manufacturing frames out of real tortoise shell. These were beautiful frames and were a breath of fresh air visually, but genuine tortoiseshell had too many complications and the frames would break very easily.
Soon afterwards genuine tortoiseshell eyeglasses was replaced with plastic. There were many different types of plastic including but not limited to cellulose acetate, cellulose nitrate, and zylonite. The plastic frames resembled real tortoiseshell frames so closely that the eye could not tell them apart. They could only be told apart by various testing methods which were devised.
These synthetic plastics required an aging process of up to a year in a special climate controlled atmosphere so that they would be properly seasoned and cured, which would enable them to last and not break or become brittle with a little wearing. The manufacturing process was a long, tedious and expensive one.
This complicated process explains the scarcity of plastic faux tortoiseshell eyeglasses. They simply did not manufacture that many. Genuine tortoiseshell eyeglasses may have been more common, but being so delicate do not last as long and most did not survive until today. Other frames from the same era such as windsor eyeglasses and pince nez are not as scarce and are much more common today.
Interestingly, vintage tortoiseshell eyeglass frames were the precursor to windsor frames, but about that another time.