Montblanc fountain pens online store in the UK: Ballpoint pens manufacturers supply their pens with a medium grade point in either blue or black ink. The most popular colours for ballpoint refills are black and blue. Red and green are common alternatives. A key difference between rollerball and ballpoint pen types is the ink the two pens use. Rollerballs use water-based ink, which can easily smudge, while the oil-based ink in a ballpoint pen dries quickly. Oil-based inks, then, are harder to smudge on the page – but ballpoint ink leaks and spillages can be difficult if not impossible to …