HDR (High Dynamic Range) images are raster graphics files that store a wider range of luminance than standard digital images. This allows them to represent scenes with a greater dynamic range, capturing details in both very bright and very dark areas. Unlike standard image formats that typically use 8 bits per color channel, HDR images often use 32-bit floating-point values to represent each color component, enabling a much larger range of colors and intensities. This makes them suitable for applications like photography, computer graphics, and visual effects, where realistic lighting and shading are crucial. HDR images are often used as environment maps in 3D rendering to provide realistic lighting and reflections. They can also be tone-mapped to create visually appealing images for display on standard monitors, although this process involves compressing the dynamic range to fit within the limitations of the display device. The .hdr format is commonly associated with Radiance HDR images, a specific type of HDR image format.