How does film degrade?

Expiration: When camera film expires, the chemicals on the film lose their potency. The silver in the emulsion degrades and lose sensitivity. The colours will lose their vibrancy and contrast will fade, and the image will become grainy. Eventually it will become unsuable. Film should have a life of 2 years after manufacture. Film with higher ISO will degrade faster. Slide will degrade faster than standard negative and is also less responsive! Black and white film lasts longer dude to the simplier emulsions and smaller amount of silver. https://expertphotography.com/expired-film-photography/#:~:text=Over%20time%20the%20chemicals%20on,film%20becomes%20foggy%20and%20unusable. Water: If film is exposed to water apart of the emulsion will give away. It may also leave droplet marks, or deposit minerals such as lime. https://amianet.org/wp-content/uploads/Resource-Disaster-Recover-FAQ-Film-Water-Damage.pdf Why does film need to be kept cold? Why does refidgeration work? Simply, low temp = slow degradation. hot or humid stoage can result in flattening or fogging https://www.harrisoncameras.co.uk/storing-camera-film/#:~:text=In%20a%20nutshell%3A,Freezing%20stops%20the%20film%20degradation.