The fogging photography, which the authors have proposed as an effective method of recording the image of electric field on photographic films, is based on the desensitizing action of electric field on the process of latent image formation. The most important factor influencing the sensitivity to a given field strength is the degree of synchronization between fogging flash and applied impulse voltage. By using simple rectangular high voltage pulses it was elaborated how the variation of leading and lagging time of the fogging flash affects the film response. It was confirmed that the ionic conductivity of emulsion grains, dominating both the rate of ionic neutralization of trapped electrons and the rate of interfacial ionic polarization induced by the applied electric field, is the key parameter that governs the leading and lagging characteristics of the film response. An example of application of these characteristics to the study of surface streamers was also described.