Which action directly reduces magnification on a dental radiograph?

• A. Place the receptor close to the tooth
• B. Increase the object-to-receptor distance
• C. Move the receptor farther from the tooth
• D. Increase beam divergence

Answer: (A)

Magnification on a dental radiograph comes from the beam spreading as it travels from the tooth to the receptor. The closer the receptor is to the tooth, the less the beam has to spread before reaching the film, so the image formed is smaller and magnification is reduced. Increasing the distance between the tooth and the receptor or increasing beam divergence makes the image enlarge more. So placing the receptor close to the tooth directly reduces magnification.