Together with this section of course should be included a reference to ink, and trying to find suitable inks for fountain pen sketching can be a salutary experience…fortunately I belong to the excellent Facebook group “Fountain Pen Sketchers” , so got lots of feedback when forced to try and get an emergency supply of black ink! I KNEW already that one should NEVER put the wrong kind of ink in a fountain pen, so was ready to make do for a while with dip pens, but the following amount of info was great! https://www.facebook.com/photo.php?fbid=1483812865063849&set=gm.2099847940285415&type=3&theater&ifg=1
I’ll also include here a reference to the travel ink bottles I use…https://www.alpinetrek.co.uk/nalgene-dose-polypropylen-storage-containers/
These bottles are ultra-reliable, but for ink I would recommend that you choose examples which have a good stable base, like this one!