Shock, vibration, temperature, and humidity changes can weaken or damage paintings and sculptures- sometimes unnoticeably. Balancing access to the public with the conservation of art has previously been solved by denying movement of exhibits or relying on past experiences that no damage has occurred with previous packing and shipping techniques. Artwork may be damaged in a variety of ways- some subtle enough to avoid detection until cumulative damage is substantial enough to notice. Paintings are a good example to illustrate some of the hazards of shipment. Corner drops to a painting deform the stretcher bars, leading to severe flaking and chipping of paint.
Vibration can induce undesirable resonance's in the painting canvas.
This leads to extreme displacements of the canvas, resulting in the canvas striking its own stretcher bars, other objects in shipment, or the side of the packing case. Temperature and humidity changes can cause swelling in the artist's medium and induce excessive stress in the fabric of the painting, which may lead to paint flaking and cracking. Recent and ongoing scientific studies of artwork and its shipping environment have led to methods to ensure that exhibitions can be held without risking damage to art during its transport. Bruce Metro of the J. Paul Getty Museum in Malibu, California, is Head of Preparations, in charge of preparing and protecting artifacts for shipment to exhibitions. The following shipment test was executed to ensure that the packing case would protect its contents, even through rough handling.