1. A method of verifying whether a product label is genuine or counterfeit which comprises: producing a counterfeit-proof label having an invisible universal product code by printing the code from a plurality of discrete views of the code on a photo chromogenic layer of a lenticular material, with each lenticule having an optical center, said printing being arranged so that at least a portion of the views of the code is printed at a pre-calculated optical blind angle in relation to the optical center of the lenticules at a normal viewing distance of the label; and viewing a label purporting to be a label for the genuine product through a digital camera having a viewing screen, said camera takes a close up view of the code on label so that the invisible code is viewed on the screen of the camera to determine if the code on the label matches a genuine code for the product.