Commenter William thankfully double checked our math and we’ve corrected a small error in our % NTSC calculation.
We finally got our hands on an iPhone 5 yesterday. I tried asking Siri if she really has 44% more color saturation but she wouldn’t give up the goods, so I went with plan B and aimed our PR-655 spectroradiometer at the phone to find out just how impressive the screen really is. A lot has already been written about this display, but not much empirical evidence has been published about the color performance. How does the screen actually stack up to the marketing claims?
In short, Apple did an exceptional job improving color saturation and display quality in general, but the unit we measured just missed the 44% more color saturation claim.
The 44% more color claim for the iPhone 5 is the same claim Apple made for the new iPad. As with the iPad, increasing the color performance of the iPhone 4S by 44% of NTSC 1953 gamut, measured using the CIE 1931 color space, would result in color saturation matching the sRGB color standard. Using these standards as the goal posts, we measured the iPhone 5 at 70% of NTSC 1953 in CIE 1931, a 39% increase from the iPhone 4S, which measured at 50%. That’s 5% less of an improvement than Apple’s 44% claim and just 99% of sRGB (measured against the sRGB primaries).
While 5% less might seem like a big deal, getting to 99% of sRGB is a major feat and will result in tremendously noticeable color improvement in the phone. Additionally, color filters are notoriously difficult to manufacture. Slight variances in performance like this are common and most likely outside the range of a just noticeable difference for the average person.
If you want to know more about NTSC, CIE and sRGB, and why we are using standards from the 1930s, I have written extensively about this issue in the past.
How did they do it?
Much like they did with the new iPad, Apple significantly improved the color filter performance† of the iPhone 5. Based on our experience, this type of improvement typically means that the display requires 20-30% more power to operate at the same brightness. Considering that the display is already a major source battery drain on the phone, this further underscores the engineering effort Apple made to keep battery life about the same as the 4S.
Let’s take a quick look at the changes in each of the red, green and blue color filters, starting with white, which is all three filters turned on:
Looking at the white spectrum of the iPhone 5, we see that the new color filters are very similar to those of the new iPad. Compared to the 4S, the peaks are slightly narrower, which improves color purity. In order to meet sRGB, they also moved to deeper reds and blues.
As with the new iPad, the biggest difference between the 4S and the 5 is in blue. Apple moved the peak to a deeper blue but, more importantly, they narrowed the filter so less green light leaks through. The green leakage causes blue to look a bit “aqua” on the 4S.
Retinal neuroscientist Bryan Jones looked at both displays under his stereo microscope earlier this week. His close-up shots really show off the difference in blue filters.
Apple again chose a slightly deeper wavelength of green which is less yellow and eliminated some of the blue leakage that had been muddying the green on the 4S.
The change here is subtle but as with the other filters, the peak is narrower, deeper in the red and leakage is reduced. One difference worth noting is that, while we are seeing less peak leakage in the red filter, there had been relatively broadband leakage across yellow, green and into blue that has been largely eliminated.
In all, it’s an exceptionally well-calibrated and accurate display for any kind of device, especially a smartphone. Apple has gone to great lengths to design a screen that brings the vibrancy of sRGB to the palm of your hand.
† If you are not familiar with color filters or the inner-workings of LCDs in general this great live teardown by Bill Hammack is well worth watching: http://youtu.be/jiejNAUwcQ8
Pingback: iPhone 5 Display vs. iPhone 4 Display – Jonesblog
I may be reading the graphs wrong, but the second chart’s blue line really doesn’t seem to be 99% of the yellow line. More like 95%
Thanks William, the 99% measurement is a different scale and the language was not clear- it is comparing iPhone 5 gamut directly to the smaller sRGB standard, not as a % of NTSC. I’ve also updated the percentages since there was also a slight miscalculation of gamut size in NTSC.
Pingback: iPhone 5 Display Vs. Spectroradiometer | AVORAH - Geek Lifestyle Reviews And Views - TECH, GADGETS, STYLE.
Pingback: Youbust - Spectroradiometer Used to Measure iPhone 5 Color Performance [Chart]
Pingback: iPhone 5 Display Tested For Improved Color Saturation
Pingback: iPhone 5′s 4-inch Display Tested For Improved Color Saturation | A-ZGSM.Com
Reblogged this on blog.fnurl.se.
Pingback: Color measuring | Michelvainfilm
Pingback: Nach 2 Wochen – iPhoneBlog.de
Pingback: Use CMYK, RGB or sRGB for publishing to iPads and Android? | Planet Quark
Pingback: Adobe’s Kuler color app is a great tool for designers but is your display accurate enough for it? | dot color
Do you think the iPhone 4s and iPhone 4 used the same color filters?
The color gamuts of the iPhone 4 & iPhone 4S were very close so it’s a good bet that they used the same or very similar color filters. The generic industry term for that kind of color filter is “CF50.” The number in this label refers to the color gamut that the color filter can create as a percentage of NTSC 1953 (in CIE 1931) with a standard white LED light source as its backlight. Both iPhone 4 and 4S produced about 50% of NTSC 1953.
Pingback: iPhone as a Client Monitor | David Lindberg
Pingback: Reading may be harmful if you spend a lot of time in front of an LCD display | Kaspersky Lab Official Blog
Pingback: Reading may be harmful if you spend a lot of time in front of an LCD display
Pingback: Leer Desde Una Tablet Puede Afectar el Sueño | Nosotros utilizamos las PALABRAS para salvar el mundo | Blog Oficial de Kaspersky América Latina
Hi,o n the iphone5 display spectra the x axis is wavelengthm and the y is?
Pingback: Reading may be harmful – We use words to save the world | Kaspersky Lab Official Blog
Pingback: Device color gamuts – oversigt – Lars’s blog