Scan Results in an Image with Greatly Exaggerated Contrast
You scan a negative with a uniform background expecting something like:
an image with highly exaggerated contrast. The preview window appears as
Cause: The black-white point function assumes that the image contains a true black and a true white. Applying this to a scan that doesn't contain one or both will result in distortions.
Remedy: The user must manually determine and set the black and white points at offsets from the darkest and lightest elements of the image. Detail Link Pending
Comment: Another common beginner's error. Most frequently this happens with low-contrast images that do not contain a true black and/or white. The black-white function in either the scanning program or the image editor assumes that the lightest tone is white and the darkest is black. The entire tonal scale is transformed. For low contrast images, the dynamic range is greatly extended. Posterization may also result from this error.