Lighting and reflections

Imaging and preservation

Glossy paper, a plastic sleeve or a raised seal can reflect light straight into the lens. A blank white patch with no visible detail does not establish that ink was erased. A shadow crossing a line can also change its apparent width.

If a signature disappears in a bright patch, keep that image and take another with diffuse lighting from a different angle, leaving the document untouched. Record the lighting change and check whether the missing segment is visible in the second photograph.

Professional source · www.digitizationguidelines.gov