did a side by side comparison study to see why the blue under painting color shows so blue in my photos. think I figured it out.
the acrylic looks bluer than the oil in the photo. Acylic test patch is on the top (see the A) Oil is on the bottom. tho' theyre the same on the real panel they look different to my camera for some reason.
I purposely did the left side of both a little lighter and that's whats causing the problem. the dark green I'm swirling in is darker than the purple. so it seems the solution to not having light saturated blue peeking out is to darken the value of the underpainting color.
see how the right side of the top panel looks ok with the dark green added into it compared to the lighter blue below in the oil panel?
yeah. glad to at least have a clue to whats been going on.