There is another portrait of her in Queen Luise of Prussia’s Subalbum, here, the aghast Lady to the left of the common girl intruding into their carriage to bother Luise on her wedding day.
Both of these images are from Wikimedia.
An older Sophie Marie is dressed warmly under a bonnet-like cap and veil and a under-garment with a high neckline worn beneath a vest-jacket.
Keywords: Gubitz, Sophie Marie von Voss, Countess, German, curly coiffure, cap, rosettes, veil, chemise, high neckline, under-bodice, collar, jacket, Minoan neckline, long tight sleeves, waist band, natural waistline, full skirt