How Chemistry Helps Make your Photos Picture Perfect

Photography in Medical Uses

Through medical imaging, we gain the ability to peer inside the human body. Techniques such as X-rays, CT scans, and MRIs provide doctors with unprecedented views of our internal structures. These advanced methods not only aid in diagnosing and treating patients but also enhance researchers’ understanding of diseases, ultimately improving patient care.

• Diagnosis and Monitoring
  High-quality images can capture details that aren’t obvious during a physical examination and can help doctors diagnose a wide range of conditions, from broken bones and tumors to heart disease and infections.
• Treatment Planning
  Surgeons can use pre-operative and post-operative photographs to plan procedures and assess outcomes. In orthodontics, for example, dental photography assists in treatment planning and tracking the progress of corrective treatments.
• Screening
  Medical imaging is used in routine screenings like mammogram, scanning to measure bone density to assess the risk of osteoporosis, and more.

Film and Photo Processing Chemistry

Picture taking isn’t just a digital endeavor. Historically and still today, film cameras have captured images that can be saved for generations. And chemistry is involved in nearly every stage of this process, from the photographic film itself, to the photo development process. Here are a few ways that chemistry is used in photography:

• Film Composition
  Photographic film is coated with a light-sensitive emulsion containing silver bromide.
• Exposure
  When light hits the silver bromide in the film, it causes the bromide to lose its negative charge to the silver, making the silver neutral. Neutral silver blocks light, while the positively charged silver ion lets light pass through. This process happens across the entire film, creating a pattern of light and dark areas that form the image captured by the camera, known as a latent image. This image is invisible until the film is developed.
• Development
  Developers contain reducing agents like hydroquinone and metol. These chemicals convert the exposed silver halide crystals into metallic silver, making the latent image visible.
• Stopping and Fixing
  After development, the film is rinsed in a stop bath to halt the development process. The stop bath typically contains acetic acid or citric acid. Next, the film is placed in a fixer solution, which removes any unexposed silver halide crystals, making the image permanent and no longer sensitive to light.
• Washing and Drying
  The film is thoroughly washed in clean water to remove any remaining chemicals. Finally, the film is dried, and the negative is ready for printing or scanning.