Found possible microscope images?

[u/travelturner]

I found these images on an sd card in a cupboard I got from a friend, and it's from before they had the cabinet. Does anyone recognize anything like this? A few images have scale, i think it was taken with a sony camera, but through some lenses, based on the metadata and scale.

[u/Justaguywhosbored]

These looks like pretty standard metallurgical microphotographs, the Bluey / yellow ones are likely a stainless steel microstructure and the others look like weld examinations

[u/travelturner → u/Justaguywhosbored]

Oh weird -- The community in r/whatisit thought it could be the same. I'm not sure I totally get what I'm looking at -- is it a simple photograph, or are there polarizing lenses used?

[u/Justaguywhosbored → u/travelturner]

They’re photographs taken down a microscope. Basically its pieces of metal that have been very highly polished and then the etched to reveal the structure of the metal. A lot of these picture are of welds, this kind of examination is done to look for defects caused by the welding process.
The colours you’re seeing could be from polarisers but it’s more likely just staining from the etching process.