[egypturnash]

Probably not, all your signatures will be with nice ink, sure, but they'll still look like ballpoint signatures rather than fountain pen signatures.

[bayindirh]

UniBall's vision elite pens shade like a fountain pen. I think it's mostly ink's behavior but it needs testing.

[GuiA]

It depends if it’s the act of signing itself that is ceremonalized, or the quality of the ink on the paper.

[chrisseaton]

What matters is that it appears to have been a fountain pen when the recipient receives it. That's probably a combination of ink viscosity, pressure on the paper, things like that.