The present invention relates to a method for establishing a pre-conditioning characteristic curve for new printing ink without a known pre-conditioning characteristic curve by a computer in a machine for processing a printed material, the method comprising the steps of: inputting a color model value for the new pinting ink; comparing the color model value for the new pinting ink with a following color model value assigned to an existing pre-conditioning characteristic curve stored in a database and determining a difference value of the color model value for the new pinting ink and the stored color model value; selecting a stored color model value with the smallest difference from the color model value for the new pinting ink and selecting a pre-conditioning characteristic curve assigned to the selected color model value; adapting the selected characteristic curve by correcting the determined color model difference value; saving the adapted characteristic curve as a new pre-conditioning characteristic for the new printing ink and using the characteristic in printing ink color pre-conditioning.