My adventures into full-spectrum infrared photography and the symbolism it holds for me.
Kodak color infrared film is an old film stock produced mostly during the later half of the 1900s. Kodak's color infrared film's biggest application was for use in military reconnaissance and agricultural aerial photography to monitor crop health. Kodak does not produce their color infrared film anymore and the global supply is nearly depleted. Widely sought by film hobbyists, the film was largely unattainable because it was not produced in consumer available formats and so to even load one of these up in a camera entailed cutting from a 3 foot wide sheet and perforating to fit into 35mm canisters.
Interestingly digital cameras are explicitly sensitive to near infrared light. Your phone camera, laptop camera, every digital camera you've utilized in your life is sensitive to light outside the visible spectrum. Within early development of digital image sensors, those great engineers were like "oh geez these things are seeing too much light, we need to filter this out!" Which led to the implementation of "Hot Mirror" glass filters. An optic that reflects infrared light but allows visible light to come through. By placing these hot mirrors over digital imaging sensors, sensor engineers were able to achieve photo representations that represented real life.