# Which factor results in parallax "unsharpness"?
a) Quantum mottle.b) Size and number of silver halide grains.c) Object, film, or x-ray source movement.d) Image magnification on double-emulsion film.
The correct answer is D. Image magnification on double emulsion film.
Quantum mottle is caused by a fluctuation in the number of photons absorbed by the fast film-intensifying screen combination. Object, film, or x-ray source movement can all cause image "unsharpness" that appears blurry. The size and number of silver halide grains contribute to image receptor blurring. Parallax "unsharpness" occurs because the double-emulsion film records a slight magnification of the image on the side of the film away from the x-ray source.
