Can’t get to sleep? Blame cyan in your PC screen

Scientists have said that the colour cyan in PC, phone and tablet screens is a hidden factor preventing people from sleeping.

In a trial at Manchester University, researchers found that higher levels of cyan – a combination off blue and green – make peopleplple feel more awake, while lower levels make them drowsier.

They showed volunteers films with different levels of cyan, then measured the amount of the sleep hormone melatonin in their saliva.

Based on the study’s results, Professor Rob Lucas and Dr Annette Allen have developed new technology called a ‘melanopic display’, letting users control the amount of cyan being shown without affecting the colour on screen. This works because the body reacts to the change even if it’s not visible to the naked eye.

Prof Lucas said the display could help “phone-obsessed teenagers to fall asleep, or support alertness in people who need to use a computer at night”.

Researchers have already found evidence that blue light from screens suppresses melatonin, disrupting your body clock. This light has a short wavelength and produces a lot of energy.

Software developers have responded to this research by adding ‘night mode’ settings to devices, reducing the amount of blue light emitted.

Microsoft for example added ‘Night light’, a blue-light filter, to Windows 10 as part of last year’s Creacreators Update. It makes the screen look ‘warmer’, applying a pale orange tint.

To turn it on, open Settings (or press Windows key+i), click System, and, under Display, click the ‘Night light’ slider on.

To change your screen’s ‘colour temperature’, click ‘Night light settings’, then adjust the slider and set a tint that suits you.

Both Android and Apple phones and tablets have similar settings.