If you have an iPad or iPhone, chances are that you periodically use it in a location or two that have very low light, where even the brightness level at its lowest settings may still cause the device to glare and be somewhat intrusive. Specific instances of this might be if you want to read in bed but have a partner who is sleeping, or are otherwise in an environment where others are enjoying the dark. In these instances, you can make use of a hidden feature in your iOS device to make its brightness even dimmer.

As part of its accessibility settings, iOS contains a number of small screen tweaking features, including increasing contrast and zooming in, similar to the screen zooming options in OS X. As part of its zoom feature, iOS supports filters where you can set your screen to black and white, or even invert colors.

These filters work by applying a different color palette to your screen’s output, which will convert all colors on it regardless of the app being used. For the filter called called “Low Light,” the color palette simply limits the overall output of each color while keeping them in the same balance, and thereby cuts down your display’s output even further than if you only use the brightness control. When used with an already low display brightness, this can make your iPad far more enjoyable when you need to use it in extremely dark conditions.

1. Use three fingers to triple-tap your screen.
2. Tap “Full Screen Zoom” and then use the slider to zoom all the way out.
3. Tap “Choose Filter” and then select the “Low Light” filter.
4. Tap outside of the settings box to close it.

Note that when enabled, this feature will still work with your standard brightness controls, but the overall brightness will be relatively dimmer than when the filter is disabled. Also keep in mind that increasing the brightness with the filter enabled simply cranks up the backlight, which will reduce battery life a little. Therefore, I recommend you disable this filter unless you need the lowest brightness level it offers.

Keep in mind that this feature is technically a part of the system’s zooming feature, which is an overlay view of your screen. In some cases, programs may have odd interactions with it, and while they will still function properly, you may see the filter disable briefly, causing the screen to blink brighter for a brief second. Despite this, with the filter enabled your iOS device should have much lower light output.