http://www.kunsthaus.ch/en/the-collection/conservation/examples-from-the-world-of-art-conservation/max-ernst/hidden-damage/?redirect_url=title%3DMeasures

Kunsthaus Zürich

Hidden damage

But what exactly had occurred when the mural was removed from the wall?  The piece was painted onto a 12 cm thick plaster wall. This wall was cut into eighteen pieces, the plaster panels were sanded down to a few millimeters and stuck onto wooden core-board.  During the removal many pieces of paint got lost, especially near the cut lines.  Unfortunately these small sections were not individually retouched; instead, entire areas of unaffected painting were painted over – all in all approximately 70% of it.  This drastically changed the overall color impression of the mural.  In addition to age-related color shifts of non-original coats of paint, a general graying has brought on a loss of luminosity and a decrease of abundance of nuances.

In addition to these invasive interventions to the original, the mural was also exposed to the influences of life in a bar for more than twentyfife years which left clearly visible marks.  Even though the mural was spatially separated from the dance floor, it was in close proximity with the guests; chairs and tables were just in front of it.  Since it was painted almost to the ground, much damage is to be expected especially in the lower areas. These damaged areas are presently not visible due to the newer, non-original coats of paint.

From the bottom third of the mural one can see where the added layers of paint are, how to recognize them and the extent of surface that they cover.  The recoated areas are clearly visible in normal light: the background has been completely and repeatedly painted over.  Within the leaves and forms there are punctual touch-ups that “jump-out” because of their colors.
From the bottom third of the mural one can see where the added layers of paint are, how to recognize them and the extent of surface that they cover. The recoated areas are clearly visible in normal light: the background has been completely and repeatedly painted over. Within the leaves and forms there are punctual touch-ups that “jump-out” because of their colors.
Under UV light further sections could be localized and clearly distinguished from the original sections, especially the yellow ones.  Those sections with added coats of paint are clearly visible particularly within the purplish-blue and brownish-blue surfaces.  Only the light green and light blue fluorescent sections have not been painted over.
Under UV light further sections could be localized and clearly distinguished from the original sections, especially the yellow ones. Those sections with added coats of paint are clearly visible particularly within the purplish-blue and brownish-blue surfaces. Only the light green and light blue fluorescent sections have not been painted over.
This image shows a schematic part of the newer coats of paint (in red) on the lower row of panels.
This image shows a schematic part of the newer coats of paint (in red) on the lower row of panels.
Detail of Panel 2. The grayish-green coat of paint is distinguishable both in color and also in texture from the original painting.
Detail of Panel 2.
The grayish-green coat of paint is distinguishable both in color and also in texture from the original painting.