Sometimes we make dumb mistakes and it takes us a long time to discover them. I’ve just realized that I’ve been assuming for months that a 3d-printed surface that looks “solid” isn’t necessarily watertight. Now that I’ve managed to figure out (I think) how to make blue-tinted silk fibroin solution for casting, my latest test trials of filling in the background of a 3d-printed plate make obvious that my solution has just been seeping into the interior of the 3d print and getting lost there!