Five years back, I wrote about F.lux, a free piece of software that reduces the blue light emitted from your computer screen at night.  I still use F.lux today, and I’m even more convinced now of its importance.

Your brain perceives blue-spectrum screen light as daylight.  Just ten minutes of looking at your phone screen has the same impact as walking for an hour in bright daytime sun. Viewing that fake ‘daylight’ at night leads your body to mis-adjust your circadian rhythms, which in turn leads to large and lasting negative health impacts.

By now, most of us are more likely to spend the evening staring at smartphone screens than computers.  But while apps like Twilight have followed F.lux’s lead on Android, there hasn’t been a similar solution for iPhones and iPads.

Fortunately, Apple has taken the matter into their own hands. Their next system update contains a feature called Night Shift, that cuts the screens’ blue-spectrum light at night.  The final release of that update is still a month off.  But it’s stable enough that Apple has just released a public beta.

It is, indeed, a beta. I haven’t had any problems with it myself, though your mileage may vary.  If you choose to install it, back up your iPhone first.  That way, you can roll back if the install turns out to be a disaster.

But, as I said, it’s worked without a hitch for me thus far.  And the new Night Shift feature makes it more than worth the chance, especially if you’re an evening iPhone reader.

You can download the public beta for free, directly from Apple.  (After you do, you’ll still need to turn on Night Shift in Settings.) And then you can get an excellent, light-unimpeded night of sleep.