minus-squaregmgmgm@lemmy.worldtoPrivacy@lemmy.ml•Do we have a good solution for public survaillence cams and Facial Recognition yet?linkfedilinkEnglisharrow-up2·edit-211 hours agoI’m thinking it’s a conflation with a basic “invisible ink” made with lemon juice. You write a message in lemon juice on paper; the juice dries clear, then you can heat the paper to darken the juice and make the message legible. linkfedilink
I’m thinking it’s a conflation with a basic “invisible ink” made with lemon juice.
You write a message in lemon juice on paper; the juice dries clear, then you can heat the paper to darken the juice and make the message legible.