Pocket-lint is hearing reports from iPhone 4S owners that the screens on their new phones are not as cool as on the previous model. Not in a Fonz "eh, that's cool" way, but in that their displays appear more yellow and, essentially, warmer overall. And, after comparing two iPhone 4S handsets to two separate iPhone 4 devices, we have to agree.

Where whites on iPhone 4 displays look bluish, bright and searing, equivalent screens on the iPhone 4S models we've been testing look yellowish and slightly underplayed. It is also apparent with greys on the newer models. Indeed, the entire colour palette is different in comparison.

Now, we're not sure how widespread this is, and there could be several reasons for the new hue, but what we do know is that, technically, the calibration of the displays on our sample iPhone 4S handsets is actually much closer to, what many believe, is the correct colour temperature for viewing video and photographs.

In home cinema, for example, professional calibrators will start with colour temperature and, although there are many that prefer a more bleached paper style white, the most popularly enforced standard is 6,500 Kelvin (aka 65K). This looks warm and slightly yellow to the naked eye.

The results of a correct colour temperature, though, are better black levels, more realistic colours and video playback performance that is closer to what the director originally intended (as his/her cameras, editing and studio equipment will invariably be set to 65K too). Additionally, as it is a standard across the industry, it is likely that, should you have your photographs professionally printed, they will look the same as they do on a correctly calibrated screen.

Perhaps this is the reason for the new, yellowish screens on the iPhone 4S. Considering the new phone's impressive camera talents, maybe their displays are correctly calibrated so that you can see your pictures in their true glory. Certainly, in our brief tests, the same images look more natural on the 4S.

Or maybe it is just a fault. After all, there were reports of yellow-tinged style screens with the iPhone 4 too.

And, of course, the screen may also mellow a bit over time.

What do you think? Have you noticed a difference in colour temperature on your iPhone 4S? And do you prefer a warmer screen knowing that it is closer to a standard colour temperature? Let us know in the comments below...