Otto Dix. Portrait of Hugo Erfurth. Techniques and Secrets
Hugo Erfurth with dog (Details of glasses)
Details of glasses
Visible light: Dix used the glazing technique to create a sense of transparency and textural delicacy, achieving the effect of volume and modelling in the flesh through the deployment of light and shadow under these glazes. The meticulous treatment of the eyebrows, painted with a very thin brush, is particularly noteworthy.

Infrared reflectography: IR shows a change in composition. In the underdrawing the glasses are larger. It is likely that for aesthetic reasons, Dix modified them, making them smaller. The firm and clean outline of the nose is worthy of note.

X-radiography: The fact that the glasses do not show up in the XR plate is conspicuous. It is possible that the materials of the pigment used to paint them do not contain heavy metals and consequently the glasses are not recognisable in the X-ray (they are painted over the finished face) except between the eyebrows. The dark area in the upper part of the nose which corresponds to the bridge of the glasses is called “paint reservation,” and the reason why it looks darker is that it was not previously painted in, leaving space to place the glasses, or, maybe, that the artist used an earth pigment through which X-rays penetrate easily.

Preparatory sketch: The size of the glasses in the preparatory sketch is larger than in the final painting and seems to correspond to the first design which shows up in the underdrawing.
Hugo Erfurth with dog (Details of the eye)
Details of the eye
Visible light: The iris is painted with a green glaze under which the grisaille is apparent. The application of white tempera adds brightness to the glance, while the use of red to underline the brushstrokes in the lower part of the eye provides depth in the maniera of the Italian Masters.

Infrared reflectography: IR shows that the eye is one of the areas where Dix might have spent more time working. The drawing is very detailed, as seen in the treatment of the eyelashes.

X-radiography: The number of layers that make up the painting is clearly shown.

Preparatory sketch: The eye appears outlined with a highly defined line. The white strokes correspond to the study of lights and shadows that Dix later used in the final painting.
Hugo Erfurth with dog (Details of the tie)
Details of the tie
Visible light: Presumably the fingerprint mark that appears on the surface of the painting next to the tie pin belongs to Otto Dix. In this artist, the use of fingers to blend colours was a common resource.

Infrared reflectography: The sketch is nearly drawn with a single, clean and accurate line.

X-radiography: X-rays show that Dix used white tempera to inject light and brightness into different areas of the tie. This is particularly clear in the detail of the tie pin.

Preparatory sketch: The tie pin is missing in this preparatory drawing.
Hugo Erfurth with dog (Details of the hand)
Details of the hand
Visible light: The underdrawing is perceptible in certain areas where it is not covered up by paint layers, as in the cuff of the left sleeve, where the red line that shows up could be red chalk. The transparency of the glazes makes it possible for Dix to create textures with effects that simulate the anatomy of the hand, as in the treatment of the flesh and veins.

Infrared reflectography: Next to the eyes, the hand is one of the most worked-out areas in the underdrawing. The result is a precise sketch in terms of the outline of the hand and the definition of the fingers and ring shaping the composition.

X-radiography: Dix built up the anatomy of the fingers with fine brushstrokes. The area corresponding to the stone of the ring stands out; it was probably made with white lead which prevents X-rays from going through.

Preparatory sketch: The position of the hand is defined through a series of lines. Traces of strokes corresponding to an earlier arrangement of the fingers, later corrected in the final drawing, can be seen in the lower part of the painting.
Hugo Erfurth with dog (Details of the dog's mouth)
Details of the dog's mouth

Visible light: Lines from the underdrawing are visible in the area of the gums due to the transparency of the paint layers.

Infrared reflectography: The line of the drawing is steady and concise. Dix used a very thin brush that helped him imitate the qualities of dog’s fur. The gums are outlined and the palate is cross-hatched.

X-radiography: There is a change of composition in the gums and teeth. An extra set of teeth appears in the X-ray, bearing witness to the correction of the canine figure. In the fur area there are slight carvings which he later filled to simulate hair.

Preparatory sketch: It is possible to observe the lines that shape the dog’s mouth into a final composition. The upper fangs are clearly visible, although they were neither traced nor drawn or painted into the final picture.