Archived posting to the Leica Users Group, 1998/03/12
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]As a rule the thicker the object (lead bags) the more energy (Xray) needed to penetrate the object. For example, xray penetration or energy is measured in KiloVolts (KV) the higher the energy the greater the interactions with objects in its way (bouncing of electrons) = fogging of film. With the emulsions today, there is less silver than old emulsions, silver being metalic, reflects the xray energy and causes the halides to be fogged. One can duplicate this scatter by piling on cassette after cassette on one another (metal casings will cause the scatter). The best way to survive airport xrays (if you have to) is to have a single layer of cassettes on the belt, making the energy lower (less mass) and reducing the scatter. If you put the film in a lead bag, the machine will automatically crank up the energy (auto exposure) on the xray and fog your film. Al