Completely unscientific comparison between two editions of the same #FountainPenInk
Pic 1,2:
Waterman Blue-Black NOS (likely early 2000s)
Retro 51 Lincoln / FPR ultraflex 14k
Pic 3,4:
Waterman Mysterious Blue (c. 2020)
Opus 88 Jazz / Regalia Crossflex
Both on Tomoe River 52gsm original
Old ink leans teal if looking closely, and the sheen looks redder. The new ink is more straight up dark blue, and the sheen looks more gold. Purportedly reformulated ~2015. #FountainPen
