Imaginarium of Tears, by Maurice Mikkers.

Maurice Mikkers is an artist and licensed Medical Laboratory Analyst from Amsterdam. In this series, he photographs his friends' tears using a microscope.

Mikkers wrote about the project in a post on Medium. In the project, he told his friends they could select a method by which he'd make them cry.

I asked them to come over and pick a way they would like to cry from. The options they could voluntarily choose from where: cutting onions, eat hot peppers, look in to a fan or cry because of sadness or happiness. To see if there was a resemblance or difference in the structure of forming tears, I took images of every tear drop under the microscope. A relatively simple and fun process, first you capture the tear with a micropipet. After you have the tear you dispense it on too a microscopic slide by making several small (2–4 mm) drops. After this step it takes some time to crystalize and settle. After the tear drop(s) are crystallised it's possible to take images and start comparing. The structures seen under the microscope and in the images are largely crystallized salt, the circumstances under which the tear dries can lead to radically dissimilar shapes and formations, so two psychic tears with the exact same chemical makeup can look very different up close.

Mikkers has worked at the Dutch National Institute for Public Health and the Environment (RIVM), and some of his research focused on the detection of Toxocara canis in Tissue by using a Polymerase Chain Reaction.

[This Isn't Happiness]