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Abstract

A method for preparing a color laser marked article using three infrared lasers L-1, L-2 and L-3 having respectively a laser emission wavelength of λ(L-1), λ(L-2) and λ(L-3) includes the steps of laser marking with the infrared laser L-1 a first color laser markable layer including an infrared dye IR-1 having an absorption maximum in the infrared region λ_max(IR-1); laser marking with the infrared laser L-2 a second color laser markable layer including an infrared dye IR-2 having an absorption maximum in the infrared region λ_max(IR-2); laser marking with the infrared laser L-3 a third color laser markable layer including an infrared dye IR-3 having an absorption maximum in the infrared region λ_max(IR-3); and at least partially exposing the color laser markable article to light having a wavelength between 520 nm and 700 nm, wherein, the laser emission wavelengths satisfy the condition of: λ(L-1)>λ(L-2)>λ(L-3); the infrared red dye absorption maxima satisfy the condition of: λ_max(IR-1)>λ_max(IR-2)>λ_max(IR-3); and the light emitted by the infrared laser L-1 passes, in order, through the third and second color laser markable layer before exposing the first color laser markable layer.

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