Why we won't know how visible the iPhone Duo's crease is for a long time

Apple's first foldable phone, the iPhone Duo, was announced earlier this month and will not reach stores until next month. One of its most discussed features is a nano-texture display that is meant to make the crease in the middle of the screen far less visible. The first hands-on impressions look promising, but the real answer will only arrive after months of everyday use.

The crease is still a physics problem

Every flexible screen bends along a visible crease, because with today's technology it is nearly impossible for a display to survive thousands of folds without any mark. Manufacturers have made that mark far less noticeable, yet it has not disappeared. Engadget's own hands-on report described the iPhone Duo's crease as "easier to feel with your finger than observe with your eyes."

Apple's answer is a matte coating applied over the display, which sharply reduces light reflection. People who have seen the device in person do not agree on the result: some say the crease is barely noticeable, while others say it is still visible and will only get worse over time.

Cumulative damage is the real test

The crease is not a fixed flaw but a condition that develops. Samsung ships the Galaxy Z Fold 8 unfolded, and the screen looks perfectly flat when the box is first opened. After repeated folding and unfolding, the crease becomes clearly more noticeable, and photos of foldables with damaged displays are easy to find online.

Only time will tell

Apple executives have publicly said they are proud of the iPhone Duo and believe it will be far more durable than its rivals. That claim can only be checked once the phone reaches a mass of consumers, and it will take even longer to learn how the nano-textured screen holds up over the years. The reviews due in the coming weeks, Engadget's included, can describe only a device fresh out of the box. What the screen looks like after a year of daily folding remains an open question, and the extreme durability tests popular with tech channels will not answer it any time soon.