Bloom-softens the focus on the image, and adds an overall suffused glow.
Gloom-dulls the highlights of the image. Can make faces or other objects look very flat. Smoothes out highlights and wrinkles --- instant complete facelifts for all concerned. For both Bloom and Gloom you control the degree of softness and the mix of the original and processed image.
Gaussian blur. Introduces a degree of softness to the focus. Gaussian refers to the mathematical underpinnings of the process.
