Receptor position to reduce shape distortion?

• A. Perpendicular to the long axis of the object
• B. Parallel to the long axis of the object
• C. At a 45-degree angle to the long axis
• D. Along the short axis of the object

Answer: (B)

Aligning the receptor with the object's long axis keeps the image true to its size and shape. Distortion happens when the object isn’t parallel to the receptor, because the projection then skews measurements along the length. When the receptor runs parallel to the long axis, the magnification is consistent along the length and the central ray can be directed so the projection is more uniform, reducing elongation or foreshortening. If the receptor were perpendicular to the long axis, or set at a slanted angle, or placed along the short axis, the image would distort the length and contour of the object, making it harder to interpret accurately. So the best position to minimize shape distortion is to place the receptor parallel to the object’s long axis.