Each brand and colour formulation has its own wiriting characteristics. and performance in various brands of pens. One of the advantages of writing with a fountain pen is the array of colours of inks.
Vancouver Pen Club
Ink Notes: Montblanc Jonathan Swift Seaweed Green
Glernn's Pens - Ink - Diamine Ink
Gourmet Pens: Ink Shot Review: Omas Sepia @GouletPens @Omas_Official
Ostrich Inks Part 1 — Mountain of Ink
Diamine Fountain Pen Ink, 80 ml Bottle, Ancient Copper : Fine Writing Instruments : Office Products
Pelikan – Hand Over That Pen
Ink color changing as I write? : r/fountainpens
About Fountain Pen Ink - Glenn Marcus Pen Page
Diamine Orange Ink Fountain Pen Ink - Glenn's Page