Diamine festive inks from the 2025 Diamine Ink-vent calendar. Individual 50ml glass bottles of each of the 25 colours from the calendar!

Diamine has been manufactured in England since 1864. Their ink is among the finest available; it's safe to use in all brands of fountain pen, even the shimmery ones and the sheening ones (but probably best to give your pen a bit of a rinse after use, just to be on the safe side). All the inks are water-based, acid-free, non-toxic and vegan-friendly. They're superb.

Not only are there a wide range of colours, but plenty of ink types to choose from as well.