The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase II project is in the development of optical security films that produce colorful reflections. Counterfeit documents and banknotes undermine U.S. economic and trade relations and place the public at risk. It is estimated that 3.3% of global trade is impacted by counterfeiting, with an associated cost of at least $1.82 trillion. Protection from counterfeiting requires a multi-layered approach with latest technological advancements and innovations in design and printing of optical security features. The microtextured films described in this proposal are based on a special optical mechanism that enables the creation of more color options and visually distinctive color changing appearances. The developed optical security films produce color as white light is reflected from microtextured surfaces. The proposed work brings innovative security features closer to market adoption and sustainable revenue. This project will enhance partnerships between academia and industry in the US and support public education in science and engineering. The proposed project will develop microtextured color-shifting security films. The technological opportunity is in the optical design of precisely engineered microstructured arrays that generate light interference and color-shifting appearance via a multi-reflection mechanism that brings overt security value. The Phase II research objectives comprise vis