What effect does the 'Gaussian Blur' effect have on an image?

The 'Gaussian Blur' effect is used to soften an image by creating a smooth transition between colors and details, effectively adding a blur. This technique is particularly useful in a variety of contexts, such as creating a dreamy effect, minimizing distractions in a background, or even smoothing skin tones in portrait work.

The effect works by averaging the pixels around a specific area, thus blending them together and effectively reducing any hard edges or sharp details. This results in a more visually appealing softness, making it a popular choice for both creative purposes and practical applications such as focus adjustments in video editing.

The other options, such as sharpening the image details, darkening colors, or increasing brightness, represent functions that the Gaussian Blur is not designed to perform. Instead, these actions pertain to different effects and adjustments within Premiere Pro that enhance the image quality or alter its appearance in ways distinct from the blurring function.