Here's DeeMac's picture again.

I've been looking at George Romney portraits on-line
(some of which are very bad copies, which is frustrating!)

Below is a link to the best of them. I understand what you mean
about the brush-strokes, and the aquarelle background. You can
find both in the Miss Willoughby picture Iinked to before.

Perhaps we need to look at specific Romney portraits to clarify this. Could you suggest a few?