Hue Saturation Lightness (HSL) file used by Adobe Photoshop, a raster graphics editing application; contains preset values for the hue (0 to 360), saturation (0 to 100), and lightness (-100 to 100) components of color appearance; used for applying color adjustments to images. In Photoshop, HSL properties can be accessed from the "Hue/Saturation Presets" option in the Adjustment panel. The AHU files that contain these properties are stored in the /Presets/Hue and Saturation/ directory of the Photoshop installation.
File extension is used by Adobe Photoshop.