From liveinternet.ru/users/lizeeetta/post322814017/.
Elizabeth's dress has a Vandycked collar and cuffs in this Basin portrait. Her bodice appears to have a pleated section over a stiff white partlet section.
Keywords: 1831, Basin, Elizabeth Alexeievna, Princess, Tsaritsa, Baden family, Romanov family, Russian, curly coiffure, attifet, veil, high neckline, lace collar, partlet, pleated bodice, long full sleeves, A-line skirt, shoes, jeweled bodice ornament, jeweled crucifix, mourning dress