I know that the negative was overexposed. I made all the prints myself both using an old Noritsu minilab machine as well as in my own darkroom with conventional enlarger. They are printable but but the exposure time is quite long. In fact the Noritsu machine complained that exposure time for printing was too long. The exposure time has nothing to do with exposure but I determine about 3 seconds or so the firework is in full bloom. Too long exposure time capture too much of the trails when it went down and I didn't like that. I would be doing it in B and close the shutter as soon as as the firework is in full bloom. I will use a lens with focal length and position so that the frame is about filled with 1 burst or 2. So I think I would use f/11 this time.