LATENT IMAGE INK

摘要

PCT No. PCT/CA92/00511 Sec. 371 Date May 27, 1994 Sec. 102(e) Date May 27, 1994 PCT Filed Nov. 26, 1992 PCT Pub. No. WO93/11198 PCT Pub. Date Jun. 10, 1993.A latent image ink particularly for use in printing forms such as games or coloring books. An offset lithographic press is used for imprinting a substantially invisible image on a sheet of standard paper. The latent ink used to form the latent image is a mixture of potassium ferrocyanide or other suitable color foxing iron complexing compounds, white ink and varnish. A developing solution such as ferric chloride or ammonium sulfate is subsequently added to the paper to render the image visible.