If you pack film in a lead bag and put it in a check in, it is likely that your bag will be opened . If you put it in a carry on, they are going to ask you to open it. Kind of defeats the purpose of the lead bag. Save your money. Pack the high speed film in a clear plastic bag. Have it "handy" when you get to security. Place it in the little bucket they give you for your watch and pocket change and explain that it is highspeed film you want hand inspected.