I'd been meaning to do this comparison for some time, but either didn't have the time, some pens wouldn't cooperate, or the inks wouldn't come out as I thought they should. Missing are Vert Empire and Perle Noire, orphaned by an uncooperating Kaweco Sport and a Penmanship's converter I gave away. I have learned a lot on these forums so I hope this also helps others, particularly when comparing specific inks, like blue greens, blue purples, reds and oranges. The paper is HP 32 lbs, which all pens glide on, except for the Waterman le Man 100 with Mandarin which doesn't like this paper and sometimes stops flowing - there is always one! Oh and a Platinum Cool only starts reliably upside down, on any paper, I thought I'd cured it but nope.
The differences between Souten, Kon Peki and Équinoxe 6 are subtle, and depend greatly on the nib and paper, and even on the pen and the time of day, as evaporation will change their colour drastically; but to my eye they clearly go from more blue to more green; they are all spectacular, Souten does have a funky smell, luckily I have a cold so I can't smell it as much right now, none of my other inks smell of anything. Some inks just make their pens glide, particularly Verde Muschiato and Verdigris.
Some inks took a long time to show their true tone, like Myosotis (can look too dark, turns into a blue black), Lie de Thé (can look like milk chocolate), Orange Indien looks spectacular in this nib, a lot more boring with finer.
...
