'Quink' Blue Black ink is dyed blue, the blue dye fades over 20 years or so as the black iron ink, that is permanent, develops. The blue dye is necessary as th

'Quink' Blue Black ink is dyed blue, the blue dye fades over 20 years or so as the black iron ink, that is permanent, develops. The blue dye is necessary as the black takes ~20 years to cure but should outlast the paper. It is well worth considering the permanence of your daily ink, many Universities have tales of lost Professors trying to re-create the now-faded notes of their youth. Will your original writing last for hundreds of years ? Pencil is a potentially very long lasting mark.