IV.A.57.     If a 400 speed radiographic receptor is replaced with a 200 speed receptor approximately the same film density would be obtained if:

    a.     The MAS is changed from 100 MAS to 50 MAS.

    b.     The KV is changed from 50 KV to 100 KV.

    c.     The focal spot-receptor distance is changed from 72 inches to 40 inches.

    d.     The film processing temperature is increased as necessary.