This is hands down the best black ink in the fountain pen community. That is all : r/fountainpens

Diplomat Black Ink (30ml Bottle) - Anderson Pens, Inc.

In Search of Reliable Pens! : r/fountainpens

Permanent fountain pen inks for ink & wash sketching - Liz Steel : Liz Steel

Manuscript Calligraphy & Fountain Pen Ink, Hobby Lobby

The results are in: the great fountain pen survey, part 1

Our Favorite Inks: Platinum Carbon Black - The Well-Appointed Desk

Ink Comparison: 32 Black Inks — Macchiato Man

Inky Fingers Currently Inked Notebook: A Review — The Pen Addict

Today's pen + ink match. What's yours? : r/fountainpens

Blackest Black Ink, Fountain Pen Ink Review

May 2021 – Chronicles of a Fountain Pen

SCRIVI PENS - Black Fountain Pen, Extra Fine Nib, Fountain Pens Set Luxury Refillable Fountain Pen with Ink Cartridges