Hi,
I'll say hello in a separate post, but this one will do as well. As a small curiosity, I wanted to show the results of negative staining, i.e., instead of cells (here - protozoa), we stain the background. Nigrosine, as a large molecule, does not penetrate cells (to a certain extent), so the cells are sometimes much brighter than the background (we get a "glowing" effect). Since it does not bind to proteins, it is, to a certain extent, viable. Together with slightly oblique lighting, it is an interesting alternative to contrast methods.
(http://mikroskopista.pl/wp-content/uploads/2026/02/SCR-20260201-nsxx-scaled.jpeg)