A method of treating a material, the method comprising the steps of: (1) contacting the material with a composition comprising an electrophilic species selected from aldehydes, succinimidyl esters, and mixtures thereof; (2) contacting the material with a composition comprising a chelating agent and/or a salt of an amine and/or a carboxylic acid.

A method of combatting colour loss from a dyed material, the method comprising the steps of: (1) contacting the material with a composition comprising an electrophilic species selected from aldehydes, succinimidyl esters, and mixtures thereof; (2) contacting the material with a composition comprising a chelating agent and/or a salt of an amine and/or a carboxylic acid.

A printing apparatus is provided that effectively prevents the risk of ink bleeding so as to obtain a high-quality print result. The printing apparatus includes an inkjet head that ejects droplets of ink using inkjet technique so as to adhere the ink to the medium, and an ultraviolet light source that radiates ultraviolet light. The ink contains a colorant, an ultraviolet absorbent, a resin, and an aqueous solvent that emulsifies or suspends the resin. The ultraviolet light source irradiates the ink adhered to the medium with ultraviolet light to heat the ink to a temperature lower than a boiling point of the ink and high enough to prevent the ink from bleeding, so that the aqueous solvent is at least in part volatilized and removed from the ink.

The disclosure relates to a method for decolorization of a dye-colored synthetic polymer, which includes the steps of treating a dye-colored synthetic polymer, such as polyester, with a treatment composition at pH 6 or less, the treatment composition comprising sodium formaldehyde sulfoxylate, water, and a ketone. The resulting decolorized synthetic polymer is then separated from the treatment composition.