Apple's iPhone 15 Can Change Color Simply By Holding It But It's A Feature Not A Bug
Apple finally unveiled its first USB-C iPhone last week, allowing a select few to get their hands on the device, but their hands are a bit of a problem. Some of those who have handled the iPhone 15 Pro have reported that simply touching the new titanium frame can leave unsightly marks that are difficult to remove. Apple says that's normal—it's a property of titanium iPhone users are just going to have to accept.
For the last several update cycles, Apple has used stainless steel in the iPhone Pro frame. It was heavier but more durable than the aluminum seen in the base model iPhone and virtually every other smartphone in the world. Titanium is even stronger, and can be lighter when combined with an aluminum mid-frame in the case of the iPhone. That's why NASA used it for wheel supports in the Perseverance Mars rover. However, titanium has noticeable optical differences when compared to aluminum or steel.
The internet is currently overflowing with pictures of the iPhone 15 Pro and Pro Max with halos around the buttons, which people routinely mash with their oily fingers. While aluminum might pick up a smudge here and there, that's all they are: smudges. Titanium is known for its tendency to show "interference colors." That's what makes it look like a metallic rainbow when heated. When you touch a piece of anodized titanium, you leave a fine film of skin oils on it. Light reflecting off the oily surface causes an interference pattern that removes some wavelengths, making it look discolored (see some examples here).
In advance of the iPhone 15 announcement, Apple patented oxide layers and finishing techniques to lessen the effect of skin oils. The company did talk up the unique texture of its new titanium iPhones during the event, but it would seem the changes aren't enough to completely alleviate the issue. And that makes sense, of course. There are few objects in the world that see more fingerprints than a smartphone.
So, are iPhone fans doomed to have blotchy titanium phones? Only if they don't take action. Rubbing the discoloration with your fingers won't help—in fact, it will make the problem worse by steading the oily film to more of the frame. According to Apple's newly updated support document, all it takes is a damp lint-free cloth. Just give the phone a quick wipe down, and the finish should be restored to its original color. It's not an ideal situation, but that's the price we will have to pay for a more durable iPhone.