Certified Professional Photographer (CPP) Practice Exam

An image on film starts with a reaction between light and what kind of crystals?

1. Silver halide

2. Gold halide

3. Metal halide

4. Silicon halide

The correct answer is: Silver halide

The reaction in photographic film is initiated by light interacting with silver halide crystals. These crystals are sensitive to light and play a crucial role in the process of capturing images on film. When exposed to light, these silver halide crystals undergo a chemical change, which is critical for forming a latent image. Silver halides, such as silver bromide, are the primary components used in traditional film photography. When light hits these crystals, it causes them to break down, leading to the development process where the areas exposed to light will form a visible image after developing in appropriate chemicals. In contrast, the other options, like gold halide, metal halide, and silicon halide, do not have the same properties or historical application in traditional photography. Hence, they are not relevant to the process of image capture in film photography. The process of capturing light and turning it into a photographic image relies specifically on the unique characteristics of silver halide crystals.