F.lux

TL; DR – f.lux website.

Winter is coming… which means the sun is going down earlier, and if you get used to working in the evening this tip might be useful for you.

Using a laptop (or any other active screen for that matter) late at night can mess up the sleep cycle. This is because the eye thinks that a screen is a sun and decides it’s still morning so there’s a full day ahead and for the next 16 hours you should stay awake.

The cells responsible for that are called photosensitive retinal ganglion cells and unlike rods and cones, they are especially sensitive to violet and blue light. This explains why normal electrical light bulbs do not interfere with them but monitors do.

It’s recommended by sleep specialists to avoid any screens 1 hour before going to bed but if you need to then this program can decrease the negative effect. It’s called f.lux and it’s designed to shift screen color temperature to the yellow part of the spectrum whenever the sun is down.

To show you the difference, these photos were made in a room with no windows, only the LED light, with white balance set at 3400k (Halogen light)

The configuration is pretty simple, you set your location

and pick the type of light:

and that’s all, f.lux will load the sun cycles for your area and adjust the screen

I also set the transition speed to “slow” as it makes working more comfortable

If you have several monitors, f.lux will affect all of them using the same settings (it’s not possible to configure different temperatures for each monitor).

If you’re interested, there is also a short Coursera course from University of Michigan regarding Sleep Deprivation, it doesn’t mention f.lux but mentions other features related to a good sleep.