by Julieanne Kost
In order to reset any slider in Lightroom, double click on the name of the slider.
Holding down the Option (Mac) | Alt (Win) key modifies the names of groups of sliders. For example, in the Basic Panel, holding the Option (Mac) | Alt (Win) toggles “Presence” to “Reset Presence”. In order to quickly reset the entire group of sliders, click the modified name (“Reset Presence”).
In addition, Option (Mac) | Alt (Win) -dragging many of the sliders in Lightroom evokes various different behaviors. For example, in the Split Toning panel, Option (Mac) | Alt (Win) -dragging the Hue slider will temporarily preview the Hue (color) at 100% Saturation (making it easier to select your desired hue). In the Detail panel, under Sharpening, Option (Mac) | Alt (Win) -dragging the Detail and Masking sliders displays a black and white preview of the mask used to suppress sharpening in lower contrast edge areas in the image). In the Basic panel, Option (Mac) | Alt (Win) -dragging the Exposure, Highlights, Shadows, Whites, and/or Blacks slider displays any areas of the image that are being clipped to pure black or white (on a per channel basis).