Why can scratches or dust have less effect on holographic data storage than on ordinary image storage?

In holography, data storage is significantly more resilient to physical damage than ordinary image storage because the information is not localized on the recording medium.1

In conventional photography, each point of the image corresponds to a specific, localized point on the film or sensor; therefore, a scratch or a speck of dust directly obscures the specific data at that location, resulting in a visible defect. In contrast, a hologram records the interference pattern of light diffracted by the entire object. Because the information regarding any single point of the object is distributed across the entire area of the hologram, the loss of a small portion of the recording medium due to dust or scratches does not result in the loss of a specific part of the image. Instead, the overall quality or signal-to-noise ratio of the reconstructed image may be slightly reduced, but the complete image remains intact and viewable.21