Insets (IMAGE) Proceedings of the National Academy of Sciences Caption Insets are optical images (upper) of the printed array at different densities, with magnified images (mid and lower insets) of sparse (blue frame) and dense regions (black frame), respectively. Credit Image courtesy of John A. Rogers Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.