• The Basics
• Eyedroppers
• Retracting-nib safeties
• Lever-fillers
• Button-fillers
• Piston-fillers
• Crescent-fillers
• Twist-fillers
• Bulb-fillers
• Pump-fillers
• Vacumatics
• Plunger-fillers
• Blow-fillers
• Touchdowns/Pneumatics
• Snorkels & PFMs
• Capillary fillers

The simplest of all fountain pens, eyedropper fillers (usually simply called "eyedroppers") have no internal filling mechanism of their own.  Most open by unscrewing the section, after which the barrel is filled with ink using a rubber and glass eyedropper.  Variants include the Parker Jointless, in which the section assembly essentially fits like a plug into the end of the barrel, and the aptly-named middle-joint, where the pen unscrews in the middle. 

Retracting-nib safety pens also fill with an eyedropper.  To fill, hold the pen cap end up, then unscrew the cap.  The nib should already be retracted inside the barrel, allowing ink to be introduced through the open barrel end. Once filled, the a safety should not be capped or uncapped unless held upright, otherwise the ink will pour out of the open barrel.  Always remember to retract the nib before replacing the cap!

Click here to see an original 1920s Waterman eyedropper instruction sheet

Click here to see an original 1920s Waterman safety instruction sheet