What Chemicals Are In Invisible Ink?
What Chemicals Are In Invisible Ink? Cobalt(II) chloride, developed by potassium ferricyanide. Iron(III) sulfate, developed by sodium sulfide. Starch, developed by iodine solution which turns starch dark blue and the paper light blue. Lemon juice, developed by iodine solution (ink turns white, paper turns light blue). Are invisible ink pens toxic? Invisible Ink Markers Light