I had this idea after reading a few articles on the web regarding how the blue light emitted by devices screen at night could affect our ability to calm down, relax and sleep well.

There is also an app for those with a jailbreaked iPhone that allows us to activate a night mode in which, blue wavelength are dimmed or simply removed from the screen output.

I made some test preset in the Intel Graphic Properties control panel to adjust my laptop screen colour and made myself some night or reading presets in which the white bluish colour of a on screen paper sheet such as a word document would turn to a yellowish “book under a candlelight” colour.

When the morning comes, I always run to switch back to normal preset since my eyes crave a bright and full spectrum display. In fact, the blue light is not bad at all. Following this Harvard Health Publication (archive link), we need it during the day to be awake, attentive and focused.

Now what if my laptop screen colour balance would by itself slowly follow the sun cycle?

Guess what, Intel added a time scheduler into their stuff!

Let start the project!

So, how did I calibrate my screen?

At first, I already appreciate the colours of my screen during daytime, when editing pictures… so the original curve the manufacturer gave to it let say is pretty acceptable. The first step was to build the opposite night time curve.

To do so, I decided the best idea was to reproduce the colour of an old yellowish book under incandescent light.

I opened an old yellowish book under yellowish incandescent light, brought my laptop screen aside, adjusted the brightness so the light reflected by the page match somehow with the light emitted by my screen. I then adjusted the colour parameters in the Intel control panel so the white of my screen looks like the same colour I can see the white page in the book.

Those pictures talk by themselves, there is a huge difference there. I locked the exposure, white balance and focus on the camera between the two takes, so the only difference is the setting on the computer side.

I then built 10 dimmed preset between those two opposite pictures. I used the time scheduler to automate the switch between those preset along the time of the day.

The result is the following: When it’s noon, my laptop has a bright screen with plenty of blue light, when it’s 5 pm, my screen dimmed to half yellowish and when it’s 10 pm, my screen looks like a book under a candle in order to let me fall asleep on the work I am not supposed to work on anymore at that time.

Hope you enjoyed this brilliant idea!

Tommy