Why does my inkjet film turn yellow?
There are a number of reasons but here is the most commonplace: Some inkjet inks, particularly water-based, have additives in them called fungicides which are added to prevent molding. The ink and film industries are great places to hide true costs: The buyer focuses on the raw-material costs and forgets true cost; in turn, the lowest sticker price usually gets the sale. Often, the films do a poor job exchanging the evaporatives in the ink, as a result more and more (very expensive) ink is required to achieve minimum density, the multi-layered inks entrap liquids in the film, it gets rolled up or laid in a stack and, finally, the evaporation process releases the liquids in the form of gasses which degrade the coating on the low-cost film. The best advice is to look beyond the package cost at the true cost of the ink and film combination. But for those bargain hunters? Minimize your layering to get just the deposit and density required. In colder environments be sure the film is about 72ºF with adequate air circulation before you put it away in storage. In warmer environments try to keep the relative humidity at a minimum before packing the positives away. In all cases, the problem goes up volumetrically: The more layers and the more coverage, the more likely your low-cost combination will cause trouble when it is archived.