Certified Professional Photographer (CPP) Practice Exam

What is the purpose of the Color Rendering Index (CRI) in photography?

1. To measure the brightness of light

2. To evaluate color accuracy of light

3. To determine the cost of lighting

4. To identify the source of light

The correct answer is: To evaluate color accuracy of light

The Color Rendering Index (CRI) serves a crucial role in photography as it evaluates the color accuracy of light sources. This index quantifies how faithfully a light source illuminates different colors in comparison to a natural reference light, such as daylight. A higher CRI value indicates that the light source renders colors more accurately, which is essential in photography to ensure that the colors captured in images are true to life. When photographers select lighting, they often look for a light source with a CRI of 90 or above, as this indicates high color fidelity, allowing for vibrant and realistic photographs. Accurate color representation is vital, especially in fields such as product photography, where discrepancies in color could impact sales and customer satisfaction. The other options, though related to lighting, do not address the specific purpose of CRI. Brightness measurement pertains to different metrics like lumens or lux, while cost considerations are not related to how color is reproduced under light. Identifying the source of light pertains more to understanding light types (e.g., incandescent, fluorescent, etc.) rather than evaluating how well colors are represented by that light source.