One thing I have done for over 25 years is to keep my own recipes for ink colors that I use consistently.  Brands of ink come and go, but by mixing my own, I can always get to a color I want.

Below is one of my ink recipes:

"LAF Cranberry"  (LAF were my initials many years ago)

I use FW Acrylic Inks, vintage Rotring Artist Color Inks, KohINoor Drawing Inks to mix my own colors.  These inks are for tecnical pens only.