What action often resulted in a dreaded ink blob when using fountain pens?

Answer

Pressing too hard, or if the ink flow was interrupted and then resumed with pressure

The issue of getting a dark, unsightly blotch occurred when too much liquid ink flooded the page, often triggered by excessive pressure or pressure resuming after a momentary interruption in flow.

What action often resulted in a dreaded ink blob when using fountain pens?
inventionHistorypenwriting instrument