When making my holographic film I have to sensitize it with a slightly alkaline dilute developer before use. Otherwise there is hardly any sensitivity. I noticed that when I leave a undeveloped piece of film in the light, it will print-out (become dark) in a relatively short time due to the dip in the very dilute developer. If I don't do this sensitizing the film is about 100 times less sensitive and there will be no print-out whatsoever if left in the light without developing. Even virgin gold sensitized emulsion does not print-out if not sensitized with a reducer before use. I noticed that COMMERCIAL film also prints-out when left in the light. So that leads me to conclude that there is likely a reducer present in it as well. Does anyone know what is used in commercial film? I have been using hydroquinone, but I am looking for a better product.