Profile: The Parker Duofold Geometric (“Toothbrush”)

(This page revised June 22, 2012)

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Duofold Geometric catalog page, 1939
This 1939 Parker catalog page shows the Standard and Slender pens, a pencil, and a boxed set, with prices.

manufacturer logo The Short-Lived “Toothbrush”: From its introduction in 1933, Parker’s flagship pen was the Vacumatic. The grand old Duofold, which had held the top honor since its introduction in 1921, was quietly retired, and it disappeared from the catalog in 1935. (But it was still manufactured at least into 1938; I have seen a black Duofold bearing a 1938 date code.) In 1939, Parker reintroduced the Duofold name, giving it to the button-filling Duofold Geometric (nicknamed the “Toothbrush” in reference to the design of its celluloid). But the new Duofold was not to take over flagship duties in Janesville; instead, it was a less expensive pen model than the Vacumatic, similar in design to the aging Challenger but with gold-filled trim instead of plated (and, as was common, nickel-plated trim on gray pens). The Geometric was available in two sizes, “Standard” and “Slender.” It had a smoothly tapered clip engraved “Parker” and a single cap band, and it featured Parker’s Visometer ink supply in the form of a partially transparent (“Television”) section. The Geometric remained on the market for less than two years; in 1940, it was replaced by the “striped” Duofold.

One “feature” of the Geometric was actually deceptive. Through the clear portion of the Television section can be seen a hard rubber breather tube. The natural assumption, that the pen’s ink delivery system must therefore be like that of a Vacumatic, is false; in fact, the breather tube is a dummy! It is only long enough to extend out of sight up into the barrel and, and there is no hole drilled in the feed to allow ink or air to pass through the tube. But it does serve a function: like the ball in a modern converter, it breaks up surface tension and promotes better ink flow.

Fountain pen Magnifying glass

This illustration shows a Standard Green Geometric. This is not
a particularly good specimen; note the discoloration of the cap
and the ambering of the Visometer section.

Fountain pen Magnifying glass

This is a Slender Geometric in Grey. The dummy
breather tube is readily visible in this image.

Although the “classic” pre-“51” Parkers are the original Duofold and the Vacumatic, the Geometric has a certain appeal for many collectors because of its unusual surface design. The Geometric was produced in only three colors (plus black); but they are attractive and unusual; even if the pen itself had no merit (an obvious falsity), it would still warrant collection for its unique surface treatment. The following table shows the colors of the Geometric. The color names are taken from the 1939 Parker catalog. (Note that this Duofold model was also available in black, as shown in the table.)


The Colors of the Duofold Geometric
Color Name

Brown Brown
Green Green
Grey Grey
Black Black

I am very grateful to Michael Richter, who initially compiled the color information, painted the color samples by hand, and has graciously given permission for me to use his work here. (3D highlighting was added with a computer, and I have altered the colors based on observation of actual pens.)


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