Artwork created in Illustrator can have white objects applied with unintentional overprint. This becomes apparent only when one turns on the overprint preview or printing separations. This causes delays in the production process and reprinting may need to be performed. Though Illustrator warns users if a white object is applied with overprint, there are scenarios when a white overprint may occur without it coming to the user’s notice. For example:
From this version of Illustrator, you have the Discard White Overprint option to remove white overprint attributes in the Document Setup and Print dialogs. This option is, by default, switched on in both dialogs . If the Discard White Overprint option is not selected in the Document Setup dialog, it can be overridden by selecting the option in the Print dialog.