What is "Vintage"?
From a collector's standpoint, the most desirable pens are those from the 1880s to the 1930s, the so-called Golden Age of the fountain pen. Pens of this era came in a vast range of styles and materials, as dozens of manufacturers competed to outdo each other in technical innovation and creative design. The Great Depression put many smaller penmakers out of business, and many of those that survived switched to war production in the 1940s, permanently abandoning the pen business.
Postwar pen production tended to be more standardized, with a handful of giant pen companies dominating the market with mass-produced models in a sharply limited number of variations. While these pens can be of excellent quality, they lack the variety and individuality of the handwork-intensive products of the prewar era.
For the most part, collectors define vintage pens as those made before c. 1965. Whether this definition will expand in years to come to include the pens of the '70s and '80s remains to be seen. Nonetheless, there is a certain logic to leaving the dividing line, fuzzy though it may be, where it is. Certain key developments of the 1950s disposable plastic ink cartridges; the soaring popularity of cheap, reliable ballpoints; the wholesale adoption of injection-molding led by the mid-'60s to drastic changes in how fountain pens were made, sold, and used. It was truly the end of an era, as many old-line pen companies cheapened their products in attempting to cut costs, then merged, went under, or retreated into other areas of manufacture. Conway Stewart, De La Rue, Esterbrook, Eversharp, Kaweco, Mabie Todd, Osmia, and Waterman USA were some of the more prominent casualties.
PS: There are those who argue that "vintage" should refer to any pen more than ten or twenty years old. While it is true that this definition is often used in other fields of collecting, there are good reasons to retain its traditional definition in ours. As used in other fields, "vintage" is little more than a fancier term for "older" or "discontinued". In pen collecting, it serves a much more specific and useful function. Most other collected items didn't undergo the same sort of fundamental shift in how they were made, marketed, and used as did pens. For pens, that shift was such a turning point that if we did not have the term "vintage" to denote it, a new term would have to be found.