Rotring began making pens in Germany in 1928, although the company originally had a different name. The Rotring name was adopted in the early '70s and means "red ring"; each Rotring pen has a trademark red ring around the barrel. The art pen can be purchased on its own or as part of a calligraphy set and is suitable for writing or sketching. It comes with filled ink cartridges, but many users prefer to use a Rotring piston-fill converter that they can fill with ink from a bottle. Use Rotring brand cartridges and converters to prevent leakage.
Remove the pen's cap. Hold the grip and rotate the base of the pen, below the red line, counterclockwise to separate the writing nib and expose the cartridge well. Set the base of the pen aside.
Pull the existing cartridge out of the nib with a straight pull and not a screwing motion. Insert the new cartridge into the nib, tapered end first, and push firmly until you feel it pop into place. Screw the base back on, and shake the pen once with a downward stabbing motion to get the ink flowing.
If you are using a piston-fill converter, dip the pen nib into the bottle of ink until it is covered. The converter acts like a permanent refillable cartridge. Twist the screw end of the converter, which creates a vacuum and draws the ink into it. You can see when it is full. Lift the pen from the ink and screw the base back on. Clean the nib with a paper towel or lint-free cloth.
Protect your work area with newspaper or paper towels before refilling.
Do not use india ink because it will cause clogging.