Date sent: Sun, 2 Jan 2000 20:04:48 -0800 (PST) From: Rolland Elliott Subject: Hasselblad Xpan Fogging reduced by using 87C gels To: infrared@a1.nl Send reply to: infrared@a1.nl I experimented with a Hassy Xpan camera over the week. Using a camcorder with sensitivity in the infrared light range, I was able to actually see the IR sensors light up as the film moved across the film gate of the camera. My motive was to try to reduce the amount of fogging that the Hasselbald produces on HIE negatives. My first attempt was to cut out a tiny piece of 87A gel and put it over the IR sensors. Unfortunately, the camera would not advance the film with this dark filter over the sensor. This was puzzling since my IR sensitive camcorder showed lots of IR light from the film sprocket sensors penetrating the 87A filter. This was probably because my camcorders CCD was more senstive to IR light than the cameras IR sensors were. Next I tried an 87B Gel; same result, camera would not advance film. Lastly I tried an 87C gel over the IR sensors, and the camera finally worked like it was supposed to. I also tried putting two layers of 87C gel over the camera's sensors and this worked out fine, but three layers of 87C gels was too much. The two layers of 87C gels greatly reduces the fogging on the Hasselblad Xpan camera to the point that it is not noticible in many shots, and hard to spot when it is present. One should be aware that switching between panoramic and regular format shots causes the camera to realign the film using the IR sensors. Therefore one can easily cause film fogging by switching between the two formats repeatedly. My advice is to keep format switching to an absolute minimum to minimize fogging. Perhaps the same technique could be used to reduce IR fogging in Canon cameras?