MicrobeHunter.com Microscopy Forum

I recall reading of a “negative” stain that is good for viewing specimens in dark field. Does anyone know what this is?
Thanks

Here are a couple of links:
https://microbiologyinfo.com/negative-s ... nd-result/
(which doesnt show any images, for me)
https://www.austincc.edu/microbugz/negative_stain.php

Funnily enough I picked up a bottle of Indian Ink the other week to give it a go, but I havent tried it yet

Thanks

We used India Ink (not Indian...) in clinical labs to help show the capsule, considered diagnostic, around the yeast Cryptococcus neoformans, primarily in spinal fluids. It worked well for blood cultures with C. neoformans as well. Gram Stains don't really show the capsule as it stains very poorly if at all. The black/brown negative stain darkens the background but doesn't penetrate the capsule or yeast cell, so the both stand out really well: https://en.wikipedia.org/wiki/Cryptococ ... _lores.jpg

Cryptococcus gattii is a newer species (and nastier) that is also encapsulated. You cannot tell the difference between them visually: https://ppdictionary.com/mycology/neoformans.htm

I've never tried India Ink using darkfield, so I could be wrong, but I don't see how it would help visualize other specimens in darkfield. If anyone has images I'd love to see them!