A half frame negative is a photographic format measuring 18 x 24mm. Images are recorded on a vertical axis on standard 35mm film, effectively doubling the number of exposures on a roll. For example, a 36-exposure roll yields 72 half frame images.
This format is useful for photographers seeking to capture more images without changing film frequently. Understanding half frame negatives helps in planning compositions, managing film usage, and achieving consistent image quality when using this compact format.