!!
or:

joyce loebel densitometer. explaining how it works is a bit complex
iirc, it had a piece of glass, about 2 inch by 8, that had a gradient of grey along the long axis (a "wedge")
you put a piece of xray film on this, and the instrument shined a light thru the film and thru the wedge

I think this is fair:
Research people (grad students, postdocs) don't really have time to "optimize" a buffer where a real optimization study might involve testing 100s of combinations of ingredients, where the ingredients are often

will cost 850 million dollars
Maybe I'm old and don't know what things cost, but that sounds like an awful lot of money to me