The electron density measurements of KNiF3, nickel potassium trifluoride, by the vacuum-camera-imaging plate (VCIP) method and using a four-circle diffractometer with scintillation counter, are performed and compared. In the IP (imaging plate) case evacuation allowed the background around peaks to be reduced 50 times, which significantly increased the accuracy of the data, especially for high-angle reflections. A new VIIPP program for visualizing and integration of IP data was designed to treat the data, in which the correction for oblique incidence was applied. The resulting electron density reproduces all the features of the accurate conventional measurement.
