HurterDriffield

The Hurter-Driffield method is a fundamental approach in photographic chemistry used to quantify the sensitivity of photographic emulsions to light. Developed independently by British chemists Henry Crossley Hurter and Dr. Vero Charles Driffield in the late 19th century, this method provides a systematic way to measure how different exposures affect the density of developed photographic film or paper.

The technique relies on exposing a series of identical photographic samples to varying intensities of light for controlled durations. After development, the resulting densities are plotted against the logarithm of the exposure values, producing what is known as the Hurter-Driffield curve, or H-D curve. This curve illustrates the relationship between exposure and density, revealing key characteristics such as the emulsion’s speed, contrast, and latitude—the range of exposures that produce usable results.

The Hurter-Driffield method laid the groundwork for modern photometry and was instrumental in the standardization of photographic processes. It remains a foundational concept in both historical and contemporary discussions of photographic science, particularly in understanding how light interacts with photographic materials. While modern digital photography has largely replaced traditional film, the principles of the Hurter-Driffield method continue to influence the development of imaging technologies, including digital sensors and computational photography.