Dividing the columns into the fluted areas and the relief surface will help me to render the shadows in both, because I’ll be able to wipe off the glazes that otherwise would be hard to control as they spill off the edges of the areas needing shadow. Because theses narrow strips of the marble surfaces have slightly different lighting on them I need to control them quite carefully. Once the flutes have dried I can work on the  cast shadows within them without worrying about the relief areas, then paint the relief shadows.
Another reason I want to paint these flutes in two stages is that I’d like to avoid the brush-marks in the vertical lines conflicting with the relief of the columns. I need the marks to follow the flutes as much as possible.
Adding the columns has really altered the balance of the painting in a positive way; the girls feel much more as if they’re within an enclosure; their destination is far more clear; the marble structures feel much more solid and interesting with the “L” shape that’s generated by that solid vertical of the pillars. I’m really looking forward to getting these pillars marbled and shaded.
