Typical of Schiele is the particular attention he pays to facial expressions and gestures. In this portrait, it is above all the strikingly highlighted hands and arms that convey an impression of dynamism and strength. The left arm rests confidently on an invisible balustrade, while the right hand is clenched into a fist. This deliberately staged gesture enhances the impression of Gerti's determination and presence. Her expressive gaze, slightly raised eyebrows and straight, almost defiant mouth also give her an energetic and self-confident aura.

Schiele was fascinated by the way in which the inner state of mind of human beings, which Sigmund Freud at this time was beginning to call their ‘psychology’, manifested itself in the facial expressions and gestures of their bodies. For Schiele, who by this point in his career considered himself something of a seer, the inner workings of the human being was a sacred fire and mystical light that burned within them like a burning passion. Schiele's approach was similar to that of the neurologist Jean-Martin Charcot, who assumed that the body, as the material container of an inner mind, would somehow physically reflect the inner workings of the mind. Schiele was drawn to all the peculiarities and extremes of physical activity and human behaviour. His drawings and watercolours are full of studies of elaborate or eccentric gestures and expressions, physical contortions and manifestations of sexual desire – the force that both Schiele and Freud saw as the primary human drive. The composition of this watercolour underscores these ideas: the empty background draws the eye entirely to the figure, thereby emphasising Gerti's presence all the more. This deliberate use of negative space, inspired by Art Nouveau, becomes a means of expressing psychological depth and emotional intensity in Schiele's work.

Gerti, who is described as a lively and gregarious personality, inspired her brother with her natural charisma. In this portrait, she is no longer shown as the shy girl of earlier works, but as a self-confident young woman. The colouring – especially the intense flesh tones – suggests an inner glow and a powerful vitality. This portrait of his sister shows both the dynamism and vitality of life and the fragility and transience that are inextricably linked with existence. The work thus becomes a striking study of human existence in all its complexity.