When storing paper, the following precautions should always be followed:
Do not store paper where it will be exposed to direct sunlight.
Store all your thick paper in the same environment - a room where the temperature is 20–25°C (68–77°F) and the humidity is 30–65%.
Store on a flat surface.
Do not store paper vertically.
Once opened, store paper in plastic bags.
Keep paper tightly sealed in a bag made of anti-humidity material even if the package of paper has not been opened yet. If sheets of paper are not stored in an anti-humidity bag, store them in a plastic bag and tightly seal it.