CF.lumen 3.74

CF.lumen adjusts the colors on your Android device based on the position of the sun or your custom configuration.

NOTE: Android 5.0 is now required. Versions up to v3.16 that support 4.4 KitKat are still available from the XDA thread (see below). Experiencing a performance drop since v3.60? Turn on performance mode.

When using the default settings, your display will get a warmer tint (lower color temperature) when the sun is down, vastly reducing strain on the eyes. Blue light makes your brain want to stay awake, and a lower color temperature reduces the amount of blue displayed; using this in the evening reduces your brain's effort to keep you awake at night.

During sleeping hours, by default, a red filter is used. Red strains your eyes the least and retains your night vision.

Light sensor

The light sensor can be used to automatically adjust the color: switch to the sleep filter in full dark or to the day filter (usually none) under bright lights.

Because light sensor quality varies wildly between devices, a calibration option is provided for experimentation.

Color filters

Several filters are provided. Those named after a color (red, green, blue, ...) do not limit the display to those colors but convert the displayed image to grayscale first, then display that image in levels of the selected color. This preserves details that would otherwise be lost.

Grayscale, invert colors, temperature adjustment, and custom R/G/B adjustment filters are also provided.

Colorblindness

The master color filter setting also has an option for colorblindness enhancement with settings for protanopia/anomaly, deuteranopia/anomaly, and tritanopia/anomaly. These options theoretically enhance clarity and color detail.

No claims are made regarding the effectiveness of these filters. These filters were conceived by Google engineers; CF.lumen just includes them.

Pro version

Upgrading to CF.lumen Pro will support development efforts, remove all nags, unlock the option to start at device boot (ensure you test your configuration first), and unlock notification options. It also enables Tasker integration.

In Pro mode, the notification adds convenient buttons to quickly disable the current filter or switch to sleep mode, and you can switch the notification to when enabled mode, which shows the notification only when a color filter is active.

In non-Pro mode, the notification only prompts you to upgrade to Pro. Although it may seem like an annoyance, it actually prevents Android from randomly killing the background service handling all the work. Disabling it without terminating the service can be achieved by navigating to Settings -> Apps -> CF.lumen and unchecking Show notifications.

Holding Chainfire3D Pro (ancient) installed will enable Pro.

Performance

When no color filter is active, there should be no noticeable performance impact. When a filter is active, impact varies depending on the device and your activity. On some tested devices, there was no observable performance impact; on others, it was slightly noticeable. Performance also depends on the driver in use.

Future

Please bear in mind that Android's rendering system evolves over time. This app may cease functioning on future Android versions without any possibility of a fix.

Scary permissions

The majority of permissions are solely used for Google Maps to set your location and Google Play for In-App Purchases. No claims can be made regarding what information Google components transmit to Google servers, but no information is transmitted elsewhere other than Google servers.

More

For advanced user information, discussions, and support, please refer to this app's thread on XDA-Developers: XDA-Developers Thread.