Just how good is the iPad’s color?

Just how good is the iPad’s color?

We often hear industry professionals complain that their work ends up being viewed on smaller and smaller screens. At the same time we increasing hear that clients want dailies delivered on iPads and we know they frequently use such devices to review work in progress. As Apple released the third generation iPad we saw two different reports suggesting that this new device had very accurate color – even describing it as being close to a professional broadcast monitor.  That claim seemed like something we should check out so we loaded up an iPad 3 with normal test images and borrowed a Photo Research PR-650 SpectraScan Colorimeter to test it. Testing a $500 consumer device that has only a brightness control with a $12,000 Colorimeter – Hey why not?


We started by adjusting the brightness control to have the display produce close to 30 footlamberts and found that with the brightness set to about 50% we were close. We then set out to measure values using images of 100% white, 50% and 10%. Here are the target values for rec 709 along with what we measured:


revised vaules (fixed typo)

That is remarkable.


And if we measure the red, green and blue bars in SMPTE color bars:


We attended a web seminar by Datacolor about their Spyder4 monitor calibration system and they mentioned they have a means of calibrating iPads and iPhones. With clients often working remotely it may not be possible to calibrate their devices – so we wanted to know just how the new iPad was right out of the box. We didn’t do this in a scientific manner especially as we used a sample size of only one iPad, but we were impressed by what we observed.

Where does this leave us?  We are impressed by the color on our iPad, just looking at images tells us a lot and comparing them visually to a calibrated client monitor is what made us want to do these tests. On a laptop there are many adjustments that can be fiddled with that can affect the image, one advantage on the iPad is there is no user accessible color control, except brightness. As you can see from the above data the iPad is remarkably close to what we would expect and we now feel a whole lot less nervous about clients judging work on them.

Special thanks to Marcus Hutchinson for his assistance with this testing.

9 Responses to “Just how good is the iPad’s color?”

  1. Scott Squires

    2012-04-26T01:35:03-05:00

    Have you tried multiple devices and compared them? How about relative to iPad 1 and 2 devices?

    Reply
    • Jeff Heusser

      2012-04-26T06:11:04-05:00

      No, as I said sample size was 1. Never tested older iPads, just the newest one – and only was drawn to do that after seeing reports that the color was supposed to be so accurate. Before I sold my original iPad I did load the same test images and did a side by side comparison and was surprised how good it held up but the idea to actually measure did not come up until after I had sold it.

      Reply
  2. Bram Desmet

    2012-04-26T08:41:36-05:00

    Jeff, is that y chormaticity value for 100% in the table a typo by chance? If not then it is actually way outside of any sort of acceptable range. Correlated color temperature by itself means very little if x,y chromaticity are not within some sort of acceptable threshold and if the deviation is really 0.054 that is actually beyond huge. FYI, my third generation iPad at 30fL showing 100% white reads x=0.3096 y=0.3218 with a CCT of 6740K as measured by a PR-655 with 5nm bandwidth option.

    Reply
  3. Tom Tcimpidis

    2012-04-26T10:11:32-05:00

    We have two new iPads and a colorimeter so I decided to measure our two just to see how close we got to your measurements. The results were encouraging as the x and y values for 50 and 10 (and x at 100, since y is clearly a typo) were all within .002 of your measurements.

    Reply
  4. Jeff Heusser

    2012-04-26T16:13:49-05:00

    Thanks Bram and Tom, I did in fact have a typo. Updated now.

    Reply
  5. Morihiko Kubota

    2012-04-27T00:34:49-05:00

    Hello Jeff,

    This is just I wanted to know.
    I translated this article into Japanese.
    If it’s allowed, I’d like to sure this topic with my friends by my translated version.

    Reply
  6. Richard Kirk

    2012-05-14T09:23:17-05:00

    Have you measured the cyan, magenta, and yellow bars too?

    The display is a LED backlit LCD. LCDs primaries are not always additive. Fringe electrostatic fields from one pixel element can have a small but measurable effect on the neighbouring pixels. If we turn on the red pixels, then a bit of the field will leak into the neighbouring green and blue pixels. This is not normally a large effect, but it is larger when the pixels are particularly small.

    I would have expected the LED backlight to give RGB primaries that are more saturated then the SMPTE primaries. Apple may be applying 1D tone curves and a 3×3 matrix to match the SMPTE primaries. This would allow them to match the red, green and blue points and the display white, but not necessarily to match the cyan magenta, and yellow corners.

    Reply
  7. Andreas Breslawski

    2012-07-02T11:00:53-05:00

    What richard Kirk says is exactly the problem I’m seeing on my new iPad. My Dell S-PVA monitor (CCFL backlight) and printed images don’t have this color problems.

    Reply
  8. Manuel

    2012-07-26T04:15:57-05:00

    Dear Jeff,

    I work with Spyder4Elite and I have seen it is not very precisse in comparison with SpectraScan. I am very interested to know luminance curves for each RGB channel with gamma. Could be possible to offer this information?

    Regards.

    Reply

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