Graphologist IsraelImaging and preservation
When a page is photographed obliquely, the side nearer the lens appears larger and the rectangle may look like a trapezoid. Differences in signature length or slope between photographs may reflect this geometry. Straight printed rules and page edges provide useful references for checking the camera angle.
If the apparent width of a contract varies from top to bottom, photograph the original again with the phone parallel to the page. Keep the uncorrected capture. A software correction creates a derivative image that should be identified separately.