These colorful butterflies were created using transparent ink
Clear printer ink gets its hues from structural color
![images of butterflies created with transparent ink](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2021/09/092421_mt_ink_feat.jpg?fit=1030%2C580&ssl=1)
Transparent ink takes on a variety of hues when printed in precise, microscale patterns across a clear surface.
K. Li et al/Science Advances 2021