these images, and I think "scientific" images more broadly, are much more dependent on discoure or narrative to draw out ethnographic meanings. what's most ethnographic about them is they way they condense a set of practices and relations: who makes them, how they are made, how they learn to make them, how people learn to read them, how they are used, etc. The genealogies of these practices in particular places.
the genre is chromatography, but of a particular kind. the material process here is actually quite interesting, and is actually much more a kind of photograph than it is akin to other kinds of chromatography; the paper is treated with silver nitrate, as photographic paper is: https://www.milkwood.net/2011/11/06/soil-chromatography-with-eugenio-gras/
but that said I also read this as a kind of mandala, or similar sort of image meant to elicit or focus meditative attention
my immediate impression is: pretty. the radial pattern is simple and pretty, something a kid would do at a fair or as part of a simple science demonstration. But then the commentary makes me wonder, intellectually, what am i looking at? What chemical reactions are behind the pattern, accounting for it? What can we learn from the different colors, the different positionings of closer to or farther from the center?