|Trade catalog from F.W. Devoe & Co., 1886.|
"The metal ferrule gained popularity in the 19th century. Mechanization eliminated the time-consuming and expensive operation of binding the hair to the handle by hand. Initially, the metal ferrules were glued to the handles, and as the moisture penetrated the wood handles the brush heads simply fell off."
"This prompted the development of the crimp, the indentations in the ferrule that secures it to the handle. In the 19th and early 20th century, some metal ferrules were nailed onto the handle, while some had single or multiple crimps."
"The round metal ferrules could be flattened, allowing for the manufacture of flat bristle brushes instead of rounds. Artists, especially the French impressionists, used these flat brushes to create a new paint stroke called the tache, a broad flat, even stroke."
|Contemporary wire-tied quill ferrules made by Pierre Finkelstein|
Before the crimp, some metal ferrules were nailed to the tip of a wood handle. But another viable method for attaching hairs to the end of a brush handle is using feather quills tied with wires. Some people, such as Pierre Finkelstein, still make wire-tied quill ferrules, saying that they allow you to hold more hairs more securely. You can also get commercially available watercolor mops tied with wires.
From The American Artist's Tools and Materials for On-Site Oil Sketching by Alexander Katlan, in Journal of the American Institute for Conservation