Pia

Unripe persimmons, the really tannic kind, are used by Japanese to create a black patina on ferrous surfaces. They also mix fermented persimmon juice with iron dust to make a back ink. I was unwilling to buy a bottle Caswells, but I remember some fruit and vegetables can really black a high carbon rustable knife, so I googled what fruit should I use to black/blue iron or steel and came up with persimmons and just so happens my neighbor has a tree next door. So, experiment coming! Nearly in season, too. Can’t find anyone that has done it on YouTube yet. I am still googling around for any info.