Disclosed are a process for inkjet printing color images on various substrates using a formaldehyde-free crosslinking agent in the ink composition, which is therefore devoid of formaldehyde emission and suitable for health-aware manufacturing practices, as well as objects having images and designs printed thereon which are devoid of formaldehyde and therefore suitable for use by infants.

Disclosed are a process for inkjet printing color images on various substrates using a formaldehyde-free crosslinking agent in the ink composition, which is therefore devoid of formaldehyde emission and suitable for health-aware manufacturing practices, as well as objects having images and designs printed thereon which are devoid of formaldehyde and therefore suitable for use by infants.

A method for coloring of cellulose in a supercritical CO.sub.2 medium by an uncharged hydrophobic dye, including at least the steps including of: (i) provision of cellulose fibers, (ii) placing the cellulose fibers in the presence of: a) an effective quantity of at least one uncharged mono organo-urea primer of formula RNHCONH.sub.2, where R represents a linear or branched, saturated or unsaturated, hydrocarbon chain possessing at least 3 carbon atoms, or a saturated or unsaturated cyclic hydrocarbon radical, which is bonded directly or via a methylene or ethylene group to a nitrogen atom, and if appropriate substituted under conditions conducive to the forming of a covalent carbamatic bond between the cellulose and the molecules of the organo-urea; and b) at least one hydrophobic dye in a supercritical CO.sub.2 medium, under conditions conducive to the immobilization of the dye on the fibers.