A method and apparatus for evaluating a soiling level of a media item, such as a banknote. The method comprises receiving an image of a media item including a plurality of pixels, each pixel having an associated intensity. Two sets of pixels are created, where each pixel in the first set has a higher intensity than each pixel in the second set. A representative intensity value from the first set and a representative intensity value from the second set are calculated. A soiling value from the ratio of the representative intensity value of the second set to the representative intensity value of the first set is calculated. The media item is captured if the soiling value fulfils a capture criterion.