Posted by einv on October 26, 2021, 2:12 am, in reply to "A free full tank"
I often do this with old piston fillers... the seal needs time to expand and find its old flexibility and what better than ink that has always contacted it. Like rain falling after drought, but slowly, with no runoff.... the ink looks to me like a blue black, one or those “writes blue but dries black” kind of a deal.