I’m now back to black ink in my Lamy cartridge pen. I ended up giving the pen a good wash between changes so I can’t say how long it would have taken to stop issuing a mixture of blue and black but I expect it would have been less time than when changing to the lighter colour. What I can see is that it took about a month (2 Feb – 1 Mar) to run through the cartridge writing between a line or two and several pages each day, so it looks like having an ink pen isn’t too expensive a habit to maintain.

Buying in batches, the ink costs around 85p a cartridge although I might consider experimenting with a converter so that I could refill from an ink bottle rather than generating another piece of waste plastic every month. Working at home, I’m less likely to be caught away from my “filling station”, although there is the potential to get very messy!