How much ink is in my fountain pen reservoir?

Fountain pen reservoirs can have extremely variable ink capacity.

You can go from a minimum amount, like that of pens fed by a typical ink cartridge (a disposable mini-reservoir that contains just over 1ml of colored liquid) to considerably larger ink reserves, up to 4- 5ml of ink.

Since the fountain pen was basically born as a portable inkwell, it is natural that there has been a constant trend to increase its capacity, but also the controllability of the levels of residual autonomy.

A bit like it happens for cars, where it is good to have constant monitoring of the fuel reserve, even in fountain pens an effort has always been made to facilitate checking the level of ink still available.

Starting from the 1930s, with the advent of ink piston filling systems and the availability of a transparent material such as celluloid, the contents of the tank began to be made visible.

And in some cases there was even the claim to quantify the number of words that could be written with the ink left available.

Stipula has worked and still works on this idea of constant interaction with the ink level of the tank.

One example is La 22, a family of piston fountain pens with ink level control window, released around 2000 and still present in the Stipula collections.

Here the piston works entirely inside a translucent chamber, both totally crystalline and coloured, as in some more scathing variants.

In any case, the ink content, of approximately 5ml, can be monitored at all times and contributes with its color tone to chromatically define the pen.