Most modern fountain pens are crafted to accept either a disposable ink cartridge or a ink converter. These are referred to as cartridge/converter fountain pens (c/c for short). Ink cartridges are usually offered in two sizes - long and short (international size). The most widely compatible ink cartridge is the international size, which can be used for 90% of all cartridge-using fountain pens. The cartridges themselves are transparent, allowing the writer to see the color in the cartridge and how much is left of it after writing. The international cartridges have a smaller ink capacity and only last a few days to a week per cartridge, depending on how much you write. The larger size cartridges may differ in shape and length from manufacturer to manufacturer. They can hold more ink for about 1-2 weeks worth of use.
A fountain pen ink converter looks like an empty ink cartridge with a turning knob (or screw) at the back-end. Inserting the converter into the front section of the fountain pen allows you to suck up the bottled ink through the nib by turning the knob, pushing the plunger up and down, like a medical syringe. Converters, if cleaned often after fills of ink, can be reused for many years and do not need to be replaced often.
Pros: Fountain pen users have the luxury and convenience of choosing between two filling options. Cartridges are easier and less prone to creating a mess while converters are more cost effective and provide a sense of nostalgia for old-fashioned pen users. Cons: Disposable ink cartridges have to be replaced more often and are less cost effective than a bottle of ink. Filling using a converter and bottle of ink can be messy for the novice fountain pen user and requires more cleaning and maintenance.
Common types of Fountain Pen Cartridges
International Size Ink Cartridge Refill
The smaller, international size ink cartridge is an adaptable fit for most cartridge or converter filling fountain pens. The slightly tapered end of the cartridge sports a collar and small bubble that is punctured when the cartridge is inserted into the front section of the fountain pen. The opposite end is usually white or an opaque material. It is common practice to "piggyback" these size cartridges inside the barrel of the pen to ensure proper fit and a readily available replacement. "Piggybacking" a cartridge involves inserting one cartridge to write with and putting another cartridge in the bottom of the pen barrel as a reserve and to keep the active ink cartridge securely in place.
Pen Brands that fit International Size ink cartridge Refills : Aldo Domani, ACME, Aurora, Bexley, Brossert & Erhard, Caran d'Ache, Colibri, Conklin, Conway Stewart, Delta, Diplomat, Edison, Elysee, Faber Castell, Foray Focus, Hauser, Inoxcrom, Itoya, Jac Zagoory, Jean Pierre Lepine, Krone, Libelle, Marlen, Metropolitan Museum of Art Pens, Montegrappa, Monteverde, Nettuno, OMAS, ONLINE, Pelikan, Porsche Design, Retro 51, Rotring, Schmidt, Schneider, Sensa, Taccia, Visconti, Waterford, Waterman, Yafa, Yard-O-Led.
Standard (International) Schmidt Ink Converter
This size converter is most common to fit full-size fountain pens. The Standard Converter looks like an empty ink cartridge that has a turning mechanism on the one end. Screwing the knob will raise and lower the plunger to draw up / expel ink from the converter. The one compatibility issue that may lead to a misfit (and inky hands) is the collar that fits to the front end of the fountain pen.
Pen Brands that fit Schmidt Converter : ACME, Conway Stewart, Delta, Edison, Laban, Libelle, Metropolitan Museum of Art, Monteverde, ONLINE, Pelikan, Retro 51, Sensa, Taccia, Waterford
Other Manufacturer - Specific Fountain Pen Cartridges & Converters
Lamy LT10 Fountain Pen Ink Cartridge
Cross Standard Fountain Pen Ink Cartridge
Waterman Fountain Pen Ink Cartridge
Sheaffer Fountain Pen Ink Cartridge
Parker Fountain Pen Ink Cartridge (also compatible with Aurora pens)
Pilot / Namiki Fountain Pen Ink Cartridge
Cross Standard Fountain Pen Ink Converter
Cross Townsend Fountain Pen Ink Converter for Townsend Pens
Pilot Fountain Pen Ink Converter (for Vanishing Point & Other Models)
Waterman Fountain Pen Ink Converter
Sheaffer Fountain Pen Ink Converter
Lamy LZ24 Fountain Pen Ink Converter for Safari & AL-Star
Lamy LZ26 Studio Fountain Pen Ink Converter