In this video I eat a little humble pie. In my last “black ink showdown” I crowned Platinum Carbon Black the winner… and then thousands of you told me I was wrong. So I went back to the lab (read: my desk) and ran a more controlled, more “scientific” set of swatches to figure out what’s actually the blackest fountain pen ink in real-world use. I put Platinum Carbon Black back on the table and pitted it against the absurdly expensive Platinum Chou Kuro, plus a stack of popular alternatives: Octopus Fluids Elephant Black, Lamy Obsidian, Diamine Forever Raven, De Atramentis Document Black, and a bonus round with Pilot Take-Sumi. I tested on Clairefontaine and Midori MD to see how these inks behave across different papers—looking at pure blackness, shading, sheen/chroma, flow/wetness, and how the lines look once everything is fully dry. I also include a waterproof check where it matters. The big takeaway: “blackest” isn’t just one thing. Some inks look dark in a wet swatch but lift into grey when dry, some are beautifully rich but expensive, and some underdogs get shockingly close for the money. By the end, you’ll know whether Chou Kuro is worth the £50 hit—or if a cheaper daily driver makes more sense.