What are soft and flexible nibs?
What is the difference between flexibility and smoothness? Why does adding flex not increase smoothness?
What Are Stock Soft or Flexible Nibs?
Stock nibs described as "soft" or "flexible" are used to achieve line-width variation by varying pressure while writing. Some of the best known nibs of this type include the Nakaya Fine Soft and Medium Soft nibs, the FA nib for the Pilot Custom 912, the nibs for the Pilot Falcon Resin and Metal Falcon series, and the Omas Extra Flexible nibs.
It is important to understand that soft and flexible nibs are actually more position-sensitive and provide a less smooth writing experience than standard rigid or hard nibs. The tines on a soft or flexible nib move independently and are more exposed, tending to catch on the paper. This scratchiness and feedback is actually a desired feature with a soft or flexible nib, but is in contrast to the smoothness normally valued when utilizing a fountain pen.
What About Customizations For Added Flex?
The same principles apply to John's customization for added flex. Whether adding flex to an already soft or semi-flexible nib, or customizing for flex a nib that is normally rigid, this customization will increase line-width variation, but will also result in a nib that provides a less smooth writing experience and is more dependent on the skill of the pen user.
Then What Are The Smoothest Nibs Available?
While both stock soft and custom flex nibs are great for artists, calligraphers, or just anyone looking to add more distinctiveness and variation to their writing, they are not designed to be the smoothest possible writers. For that, look to standard stiff nibs. And remember that any pen or nib unit you purchase from Classic Fountain Pens, whether stiff or soft, standard or customized, will be tested and optimized for your personal writing characteristics before it is shipped on to you.