No abstract

1 It is well known that, under certain conditions, a relatively weak magnetic field (<1 T) can affect the kinetics of radical chemical reactions [1,2], as well as the mechanical and electrical properties of crystals [3][4][5].In addition, there is information on the effect of a magnetic field on the properties of photographic materials in the course of preparation of silver halide photographic emulsions [6]. The aim of this study was to reveal possible influence of weak magnetic fields on the photographic properties of commercial emulsions and, using a luminescence measurement technique, to determine changes in these materials after treatment. EXPERIMENTALThe effect of a weak magnetic field on the properties of photographic materials was studied by two procedures. In the first case, the blackening of exposed emulsion layers was measured at various development times. In the second case, the characteristic curves obtained with and without exposure to a magnetic field were compared. Let us consider the former experimental procedure in more detail.After the exposure of a photographic plate within the linearity range of a characteristic curve, it was developed in a constant magnetic field of 0.55 T. For this purpose, a bath with the photographic plate was placed between the poles of a permanent magnet so that a gap was left between of the tips and the emulsion layer (Fig. 1). The bath was made of aluminum foil and mounted on the other tip of the magnet. The developing solution was gravity-fed from a reservoir so that the plate was always washed with a fresh portion of the developer. In addition, this minimized the possible effect of capillary phenomena between the tip and the plate. As shown in Fig. 1, the developer level always remained constant because of an appropriate arrange-1 E-mail: volarma@org.vrn.ru ment of the emptying fitting. To decrease the effect of capillary forces, the flat area of the upper tip was immersed below the developer level. The development was performed for a time from a few seconds to 2 min. After development, the plates were fixed in an acidic fixing solution, dried, and photometrically examined with an MF-2 microphotometer.The photographic characteristics of magnetically treated and untreated photographic plates were measured with the use of an STE-1 spectroscopic instrument with a nine-step attenuator. The characteristic curves were constructed on the basis of the spectral lines of an arc source in the region 460-480 nm.The continuous luminescence spectrum was measured using an ISP-51 spectrograph with an FEP photoelectric attachment. Emission was detected in the single-photon counting mode. Luminescence was excited with 365-nm radiation isolated from the spectrum of a DRK-120 stabilized mercury lamp with UFS-6 and SZS-21 filters. The test sample and a reference sample were placed in an optical quartz Dewar vessel with liquid nitrogen. The sample holder could be transferred between strictly fixed positions transversely to the optiAbstract -The effects of weak constant and pulsed magnetic...

No abstract

No abstract

No abstract