Micro-optic security device with enhanced wet-harvest resistance

A method for providing a wet harvest indicating security document, the method comprising:

• embossing a section of a micro-optic security thread at a predetermined pressure in an embossing die having a male half and a female half, the micro-optic security thread comprising a polymeric substrate having a first side and a second side, wherein a layer of icon elements is disposed on the first side of the polymeric substrate, and a layer of micro-optic focusing elements is disposed on the second side of the polymeric substrate;
• forming a web of a substrate in a paper making machine, wherein the web comprises a length of cellulosic material formed at a wet end of the paper making machine and maintained under tension between the wet end of the paper making machine and a dryer section of the paper making machine;
• forming a watermark feature in the substrate at the wet end of the paper making machine;
• adhering the micro-optic security thread by positioning the embossed section such that the layer of icon elements contacts at least a portion of the web comprising the watermark feature;
• and
• passing the portion of the web comprising the watermark feature and the adhered micro-optic security thread to the dryer section of the paper making machine.