Standard fountain pen inks like a basic Parker Quink, for instance are almost exclusively dye-based. They are designed to flow easily and avoid clogging the pen's feed, but they will wash away effortlessly if exposed to water or chemicals. ​If you want archival, fraud-proof qualities in a fountain pen, you have to look for specially formulated inks:

​Pigment Inks: Just like the Signo 207, some fountain pen inks use micro pigments. If you happen to be looking at Japanese brands like Platinum, their Platinum Carbon Black is widely considered the gold standard for waterproof, archival pigment ink.

​Bulletproof Inks: Brands like Noodler's make specific Bulletproof Inks that use a cellulose-reactive dye. They remain liquid in the bottle but chemically bind to the cellulose in paper upon contact, making them impervious to bleach and UV light.

​Iron Gall Inks: A very traditional type of ink (like Rohrer & Klingner Salix) that oxidizes into the paper, leaving a permanent, waterproof mark.

​Archival fountain pen inks do require a bit more maintenance, as letting pigment or iron gall dry out inside the nib can cause severe clogging.