Abstract: An ink composition, preferably for ink jet printing, contains a liquid carrier, a colorant, and a polyalkyleneimine/alkylene oxide block copolymer, preferably polyethyleneimine/propylene oxide/ethylene oxide block copolymer, and/or a primary or secondary polyoxyalkylene amine.

Abstract: Sympathetic ink compositions particularly adapted for use with high speed, non-impact ink printing equipment are disclosed, together with methods of use and development thereof. The inks of the invention are water-based and include of from about 4-20% by weight of a water soluble transition metal salt (e.g., nickel sulfate), together with of from about 2-4.5%, by weight of n-butanol or 2-butanol. After application using, e.g., ink jet printing equipment, the resulting inked images are invisible to the naked eye, and can be selectively developed through use of color-forming developers such as dimethylglyoxime- or oxalic acid-type aqueous compositions.