I had the unfortunate occasion to put this ink to a hardcore test as a pipe burst right over my desk. All my paper were soaked and dropping water for 24hours, including my grading book. The diamine strawberry red (not waterproof) became a stylish watercolor wash when this Platinum Pigment Blue didn't move a bit. It saved all the grades I recorded in blue!
The ink flows very smooth out of my pilot metropolitan fine nib even on cheap students notebooks.
This ink behaves well in the pen and does not feel different from regular dye-based ink. It does stain the converter (or maybe the silicone grease in the converter) a little if you keep it there for significant periods of time. I have not used this ink long enough to comment on maintenance, but dried bits on the pen do seem to wash off rather easily.
On paper, It is very slightly more prone to feathering and bleed-through than Noodler's black but behaves well on most papers. It behaves very similarly to Noodler's black and is as permanent as Noodler's black. On more absorbent papers this ink is a mature, muted blue. On less absorbent papers, this ink displays a slightly higher saturation and vibrancy and gains a gel-pen-like look. This ink shades rather well.
Overall, this seems like a good workhorse blue ink, especially if permanence (this is one of the most permanent blues available) and good behavior required. The bottle is well designed, which is a small plus.
