Another long lasting standard ink. According to internet reference, 4001 started since 1898 with other lines like 2001, 3001, 5001, and 6001. Now in 2016, we probably only know 4001 and Edelstein.
I’m not sure if the formula is staying the same but this black is really, black. Not as Sailor Kiwa-Guro (極黑) has water resistant and shining after drying, 4001 Brilliant Black is simply black without other trace of possible blue/green/purple from the drip test. Standard drying time, standard no shading, standard flow, and standard no bleeding through iPaper UCC and DoubleA.
If I don’t need water resistant or EtOH resistant (don’t ask why), this will be the ideal ink for black – since this ink comes as cartridges, 1 oz, 2 oz, and 1 leter bottles, lol
CP value: 95/100, considering the cost. 5 points off for no water or EtOH resistant.