I was going to ask: is this a matter of warm grey/neutral grey/cool grey?

The oatmeal yarn is a staple of fly-tying and it has always seemed warm (a pale tan) to me. Greys can be cool and have either a blue or green cast to them while the warm greys can appear yellowish or magenta-ish. Not to muddy the subject...I just wonder where a stone grey falls in. In a past life I was a catalog photographer and the clients were very particular about how colors were rendered.

Best

AA