Viewed head-on, the crease on the iPhone Duo's 7.6-inch inner display is barely noticeable. But Apple does not say the crease has disappeared. Its announcement says only that a Nano-texture finish gives the display a matte surface that reduces glare and reflections and makes the crease less visible. Because the finish works by scattering light at the surface, it affects not just ambient light but also how the display's own light looks. The microscopic surface structure may also influence how fingerprints and other smudges stick and how easily they come off. What does the less visible crease cost in image quality and ease of care? This article looks at early hands-on reviews, microscope observations of the surface, and measurements of other Nano-texture products to weigh the benefits and drawbacks.
Why Nano-texture makes the crease less noticeable
According to Apple's announcement, the iPhone Duo's inner display uses a cover layer made of a proprietary polymer, finished with Nano-texture and a scratch-resistant coating. Apple says this cover layer is up to 40% stiffer than other materials used in the industry. At the center of a foldable display there are slight dents and sags caused by repeated bending. On a glossy surface, ceiling lights and windows reflect like a mirror, and the reflections distort at the crease, making the unevenness stand out.
For example, if you reflect a fluorescent light in a polished metal plate and bend the plate slightly, the reflected image bends too. The same thing happens at the center of a foldable display. Tom Marieb, Apple's vice president of hardware engineering, told TechRadar that glossy displays have strong specular reflection, so small surface irregularities are easily emphasized visually. By his account, Apple chose a matte finish not only to reduce glare but also to make shape changes from hinge aging less noticeable.
Nano-texture scatters incoming light in many directions through its fine surface structure. Because clear reflected images are harder to form than on a glossy surface, distortions in the reflection at the crease become harder to perceive. It is similar to how a fluorescent light doesn't mirror in a sheet of paper the way it does on a glossy screen. But unlike paper, a display emits its own light. Light from the pixels also passes through the textured layer on its way to your eyes, so the scattering effect may influence sharpness and contrast, not just external reflections.
Hands-on reviews praise the reflection reduction. Gizmodo, in its launch-day hands-on, described the inner display as paper-like and almost non-reflective. TechAdvisor also judged that reflections are strongly diffused. The display evaluation site RTINGS, which examined the Nano-texture glass on the MacBook Pro, described the finish as a nanometer-scale etched surface treatment, distinct from ordinary coatings. It also found that the glass is not fully matte and behaves more like a semi-gloss, with the faint outline of bright light sources still visible. However, the MacBook Pro's glass and the iPhone Duo's polymer cover layer are different materials, so the degree of scattering may not be the same. Apple has not published data that allows a direct comparison of the optical properties of the two products.
Some reports go further into the iPhone Duo's surface structure. According to MacRumors, the display layer has tiny lens-like structures formed for each pixel using maskless laser lithography. However, Apple's announcement and Japanese product specifications contain no description of this manufacturing method.
MediaStorm's microscope observations capture features close to that report. In a test introduced by iSpazio, the iPhone Duo's surface showed an irregular structure resembling a tiling of tiny lenses. Unlike the regular arrangement seen in the iPad's Nano-texture glass, it reportedly suppressed reflections slightly more than the iPad's glass. Still, observing the shapes alone cannot confirm the manufacturing process reported by MacRumors.
Nano-texture is also not the only crease countermeasure on the iPhone Duo. Apple also uses high-strength glass above and below the display panel, a proprietary adhesive that lets the layers slide like book pages when folded, and a hinge structure that supports the center of the screen when unfolded. These address the stress of folding and the screen's shape when open, and play a different role from the reflection control provided by Nano-texture. The crease's low visibility cannot be attributed entirely to the surface finish.
The crease is harder to see, but the physical dent remains
Apple's wording on crease improvement is cautious. The announcement says the crease's visibility is "minimized," and the official FAQ describes the inner display as very flat and smooth. But in answering questions about whether a crease exists, the FAQ does not directly state whether it does.
Independent reviews agree that the crease is hard to see but not gone. Gizmodo reported that the crease can be seen from certain angles but bothered the reviewer only when the screen was off. It also said the hinge gears sit beneath the crease, and a dent can be felt when tracing it with a finger. 9to5Mac likewise said it could see the crease only under bright lighting such as sunlight, when showing black loading screens or dark scenes in video. According to MacStories' roundup, The Verge's review also found that the crease is invisible in most situations but definitely noticeable by touch.
Meanwhile, TechRadar reported that within 24 hours of the announcement, a photo showing the crease was posted on Reddit. At certain angles and lighting conditions, a dent running vertically through the center of the screen is clearly visible. In other words, what Nano-texture improves is mainly the crease's visibility, not the physical unevenness itself.
How the crease changes with long-term use is a separate question. As far as can be confirmed, there are no reports directly tracking changes over months of daily use. Mechanical open-and-close tests, however, have reported changes in screen shape.
HTX Studio opened and closed the iPhone Duo 3,000 times, stored it closed, and then measured the screen shape. The height difference between the crease's peak and valley reportedly rose from 48 micrometers (μm) before the test to 167 μm. TechPi also covered the result. Because the test included storage in the closed state as well as folding, however, the change cannot be attributed to folding cycles alone. And the figure is a measurement of screen shape, not an indication of how noticeable the crease actually is.
MediaStorm also ran its own folding test. According to iSpazio's coverage, the crease had deepened by 500 cycles, but touching it or displaying a bright image showed almost no difference. After a 10,000-cycle test and a 1,000-cycle test in a low-temperature environment, it reported the crease had deepened further. No specific depth figures were given for the later changes. The shape change measured by HTX Studio and the visual change observed by MediaStorm need to be kept distinct.
On hinge behavior, Joanna Stern ran a test opening and closing the iPhone Duo 32,000 times by machine. According to MacStories' summary, the hinge became slightly stiffer afterward, but it felt almost the same as on day one. Marieb says a matte finish shows aging less than a glossy one, while also saying, in effect, that Apple should be held responsible for judging long-term performance.
Apple has not published an official durability rating for how many times the iPhone Duo can fold. According to MacRumors, rival Samsung's Galaxy Z Fold8 has a 500,000-cycle durability rating. Figures obtained under different test conditions cannot simply be used to compare product lifespans, however. 9to5Mac also noted that its review period was only one week, so it could not judge long-term durability.
A 2,000,000:1 contrast ratio doesn't tell you how blacks look in bright light
In Apple's official specifications, both the inner and outer displays of the iPhone Duo have a typical contrast ratio of 2,000,000:1. The Japanese spec page lists the same figure, and only the inner display is noted as having the Nano-texture finish. However, no details are given on whether this contrast ratio was measured in an environment with ambient light. So even with the same rated contrast ratio, blacks on the two screens will not necessarily look the same in bright places.
The brightness of black that actually reaches the eye changes not only with the display's own emission but also with ambient light reflected off the screen surface. On a glossy display, ambient light reflects mainly in a particular direction, so blacks feel deep if you view from an angle that avoids reflections. On a matte finish, incoming light scatters in a wide range of directions, so ambient light overlays black areas faintly and blacks can look grayish. This is general optics and does not show how large the difference is on the iPhone Duo. Tom's Guide also lists drawbacks of matte displays: slightly lower contrast, raised blacks in bright rooms, and reduced sharpness and color vividness when viewed at an angle.
One example of a numerical test of Nano-texture's effect is RTINGS' measurement of the MacBook Pro. But that was a glass Nano-texture display, different from the iPhone Duo's polymer cover layer. In RTINGS' comparison, the Nano-texture model had lower contrast than the glossy model, and its black level rose sooner when viewed from above or below. Its color gamut matched the glossy model and color accuracy was maintained. However, the glossy model's distinctive impression of colors popping was weaker, and a haze, as if a thin filter had been laid over the whole image, was also noted. These results help in understanding the effect of surface light scattering, but they are no basis for concluding that the iPhone Duo changes to the same degree.
Hands-on reviews of the iPhone Duo also raise several points about black depth and color vividness. Gizmodo judged that the inner display's colors lack vividness, as is typical of a matte finish, and that its blacks are not as deep as those of the glossy outer display. Even so, it said it supports Apple's choice when compared with other foldables whose reflections and creases stand out. MacStories also cited Tom's Guide's Mark Spoonauer as saying brightness is sufficient but it falls short of the deep blacks and vivid colors one expects from OLED.
TechAdvisor also reported that dark footage doesn't get the deep blacks of a glossy OLED and looks washed out in some scenes. The same review also says both displays' colors are vivid, but that is not an assessment of the inner Nano-texture display alone, nor a direct comparison with the glossy outer display. MediaStorm also reported that under strong light, contrast drops clearly compared with a glossy display and image vividness suffers.
These reports suggest that rather than the color gamut itself narrowing, the impression of color vividness may be changing because of the light-dark difference with blacks and light scattering. RTINGS' findings on the MacBook Pro are consistent with this interpretation. As far as can be confirmed, however, no results have been published that directly measure the iPhone Duo's color gamut or color accuracy and quantify the effect of Nano-texture. A subjective assessment that colors don't look vivid should not be confused with a measurement showing a narrower displayable color range.
The advantages and disadvantages of a matte finish also vary with ambient brightness and light source position. Gizmodo reported that even outdoors in direct sunlight, it could clearly see the inner display thanks to Nano-texture's reflection suppression. TechAdvisor also praised outdoor visibility but said that by a window the screen doesn't look as good as a glossy display. Given that MediaStorm confirmed reduced contrast under strong light, fewer reflections making content easier to read does not necessarily mean black depth and contrast are preserved.
9to5Mac saw the crease when displaying dark images under bright lighting. That condition also overlaps with situations where ambient light scattering readily causes raised blacks. However, 9to5Mac did not directly analyze a link between crease visibility and raised blacks. Whether the two are related must be judged after measuring the optical properties.
Fingerprints are less visible, but some say smudges are hard to remove
Opinions are also split on how the Nano-texture inner display handles fingerprints and oily smudges. Apple's official specifications state that both the inner and outer displays have an oleophobic fingerprint-resistant coating and an anti-reflective coating. However, no detailed official explanation can be found of how these coatings are combined with the Nano-texture cover layer.
On the positive side, PetaPixel reported that the inner display makes fingerprints very hard to see. It said they were visible only when the screen was off and tilted to an angle where reflections show. CNN's Japanese edition also briefly judged that the inner display seems to resist fingerprints. These, however, are mainly impressions of how fingerprints look, not measurements showing that dirt itself is less likely to adhere.
Other reviews point to difficulty removing smudges. 9to5Mac reported that fingerprints on the inner display are slightly harder to wipe off than on a glossy display. In Joanna Stern's video review, fingerprints are described as remaining as if soaked into the screen and being far harder to remove than on a glossy display. Stern also complained that she wished a $9 polishing cloth had been included. TechAdvisor, for its part, recommends keeping a cloth handy because both the inner and outer displays pick up fingerprints, but that is not a comparison of how easily each cleans.
On October 21, a video also spread that called the iPhone Duo's inner display a "fingerprint magnet" and claimed some smudges can barely be wiped off. The video was posted on YouTube and elsewhere by Tim Pan.
According to Pan, fingerprints can remain strongly on the Nano-texture surface, but for most people the dirt came off with a single wipe. For one or two of his colleagues, however, sweat, skin oils and some cosmetics stayed on the surface and could hardly be removed by ordinary wiping. That means how much dirt remained varied greatly by user.
To investigate, Pan had an expert take a mold of the surface and also observed it under an atomic force microscope. He says he confirmed that the iPhone Duo's surface has fine irregularities with greater height differences than Nano-texture glass or typical matte films. He explains that, particularly for people whose hands sweat easily, dirt tends to remain in the surface grooves, and removing it requires cleaning fluid together with a cloth.
The differences between reviews are easier to understand when you consider that they evaluate different properties, and that how dirty the screen gets may vary with the condition of the user's hands. Reviews saying fingerprints are inconspicuous mainly judge how the screen looks in use, while those saying they are hard to remove focus on its state during cleaning. MediaStorm's result is similar: most people wiped it off easily, but for some the dirt remained strongly. However, no test could be found that applied the same dirt under the same conditions and compared wipeability across multiple displays. For now, fingerprints being inconspicuous cannot be equated with dirt coming off easily.
Considering the surface structure, oils and similar substances getting into the grooves of the fine irregularities may make dirt more likely to remain. MediaStorm's microscope observations are consistent with this explanation. As a general optical phenomenon, when oil fills fine irregularities, light scattering weakens in just that area, and the difference in reflection from the surrounding matte surface can show up as a pattern. But no report has confirmed that this actually happens on the iPhone Duo's cover layer, so it cannot be asserted as the reason smudges stand out.
Apple has also published official care guidance. A support document dated October 23 states that the iPhone Duo's inner display has a Nano-texture cover layer and advises using the Apple Polishing Cloth, a microfiber cloth made for electronic displays, or a cotton-elastane blend cloth. For stubborn smudges, it says a cloth dampened with 70% isopropyl alcohol may be used only if necessary. It also explains that while Nano-texture specifications differ by product, the cleaning method is the same. Even if smudges remain, you should follow the official care method rather than using strong cleaners or abrasives on your own judgment.
Nano-texture's pros and cons depend on where you use it
Taken together, the major reviews we could confirm largely agree that Nano-texture makes the crease less noticeable. Meanwhile, four outlets (Gizmodo, Tom's Guide, TechAdvisor and MediaStorm) pointed to reduced black depth and color vividness. On fingerprints, positive assessments that they are hard to see sit alongside negative ones that adhered smudges are hard to remove. Most of these, however, rest on visual impressions and use, and quantitative comparisons under identical conditions are limited.
| Item | Positive assessments | Noted drawbacks and issues | Basis and limits |
|---|---|---|---|
| Crease visibility | Almost invisible head-on (Gizmodo, 9to5Mac, PetaPixel) | Visible at certain angles or with dark content under bright light, and the dent can be felt by touch. Folding tests also showed shape changes (HTX Studio, MediaStorm) | Multiple hands-on reviews judged by eye. HTX Studio quantified the height difference. MediaStorm also reported changes but gave no specific figures |
| Black depth and color vividness | Few reflections even outdoors, so content is easy to see (Gizmodo, TechAdvisor) | Blacks are not as deep as the outer screen and colors are less vivid (Gizmodo, Tom's Guide). Blacks lift in dark footage (TechAdvisor). Contrast drops under strong light (MediaStorm) | Mainly visual assessment. MediaStorm's comparison and RTINGS' measurements of a different material on the MacBook Pro are useful references, but quantitative data on the iPhone Duo itself is lacking |
| Fingerprints and smudges | Fingerprints are inconspicuous (PetaPixel). Seems resistant to fingerprints (CNN Japanese edition) | Harder to wipe than a glossy screen (9to5Mac, Joanna Stern). Smudges remained strongly for some users (MediaStorm) | Mostly visual and usage-based assessment. MediaStorm examined the surface under a microscope, but it was not a cleaning comparison under uniform conditions |
What this comparison shows is that several reviews recognize an improvement in crease visibility, while the methods for evaluating image quality and cleanability are not standardized. In particular, how much Nano-texture changes the look of blacks and colors cannot be judged quantitatively, because measurement data for the iPhone Duo itself is lacking. And since fingerprints being hard to see and smudges being hard to remove can both be true, the assessments are not simply contradictory.
What decides real-world usability is the environment in which you use the device. If you spend a lot of time checking maps or web pages outdoors, the benefit of fewer reflections may matter more than a modest loss of black depth. But MediaStorm reported that contrast drops under strong light, so readability and image quality will not necessarily both improve. TechAdvisor's view that a glossy display looks better by a window also suggests that impressions can change with light source position and displayed content, even in the same bright environment.
RTINGS also lists, as factors in choosing the MacBook Pro's Nano-texture display, whether you often use it in bright environments or outdoors and whether reflections bother you. On the other hand, people who often watch photos and video in dark rooms may value the deep blacks and vivid colors of a glossy display. When RTINGS staff compared glossy and Nano-texture MacBook Pro models, many chose glossy. Those who accepted Nano-texture cited mainly using the machine for work. But that is an assessment of the MacBook Pro, and it cannot be said that the same preferences hold for the iPhone Duo. RTINGS recommends checking the actual device in a store before buying.
Going forward, three things will matter in evaluating the iPhone Duo's Nano-texture: how the crease changes after long-term use, black levels and contrast measured with ambient light brightness held constant, and smudge-wiping tests under uniform conditions. Once third-party measurements on these are available, differences in image quality and cleanability that currently rest on each review's subjective impressions can be compared more objectively. The iPhone Duo went on sale in Japan on October 23, and it can now be evaluated in real-world use. Checking not only the benefit of an inconspicuous crease but also visibility in bright places, image quality with dark content and ease of daily care is the key to judging whether this product suits how you use it.