From carolathhabsburg.tumblr.com/image/59402279506; I removed a faint watermark, probably from the Hesse state archives, and some flaws from the image with Photoshop and removed the sepia tone.
Princess Irene is shown to be pretty as well as showing what a formal curly coiffure looks like in this photo. While she may wearing a décolleté dress, I cannot resolve the neckline. The shadow cast by her bodice suggests she is wearing an under-garment about 15 cm beneath her chin. The mildly upturned sleeves suggest this photo dates from about 1890.
Keywords: Princess Irene of Hesse, Princess Heinrich of Prussia, Princess, Hesse family, Hohenzollern family, German, curly coiffure, hair jewelry, revers, necklace, choker necklace, earrings