Brightness is a description of light output, which is measured in lumens. At max brightness, the Stack Downlight outputs 750 lumens and the Stack Classic outputs 800 lumens. When using the light level slider, you’ll see brightness expressed as a percentage of the maximum lumens.
Color temperature is most simply described as a method of characterizing the color of light, usually either warm (yellowish) or cool (bluish), and measuring it in Kelvin (K). Standard Incandescent bulbs typically measure around 2700K (yellowish), where daylight measures around 5500K (bluer).
There is a list of preset options available within room controls:
Relax, Neutral, and Focus set a room's brightness and color temperature to predetermined levels set by Stack.
Auto returns the rooms to the Automatic Lighting Plan.
Off turns off all room lights and keeps them in an off state. If the light switch is toggled off and on, the lights will continue to appear off even though they are receiving power.
Sleep also turns off lights. But, rooms set to Sleep allow their lights to turn on to a maximum brightness of 10% when motion is detected*. By changing the Nightlight Timeout you can even determine how long the lights stay on while the room is asleep. This is a perfect way to gently light the way at night.
*When Nightlight is toggled on --- see Room Settings for more information. If Nightlight is toggled off, the lights will stay off when sensing activity.