About sRGB, and why you should care

Discussion in 'iPhone' started by Otto J, Sep 13, 2012.

  1. Otto J, Sep 13, 2012
    Last edited: Sep 13, 2012

    Otto J macrumors member

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    Oct 22, 2010
    #1
    Right, let me start by explaining my background: I have worked several years as a professional calibrator working with flatscreens and home cinema projectors, as well as a few TV and movie studios. I consider myself a fanatic on every aspect of image quality, and I believe the best picture at home is delivered by adhering to the standards that was used when the content is created. That allows you to see the content the way the content creator thinks it should look.

    Now, looking at different forums I see a lot of discussion about why the iPhone 5 isn't 720P, why it is "only" 640p (simple answer is it doesn't really matter on that size screen anyway). So obviously people are concerned about watching HD pictures with the highest possible quality on their iPhone. Yet when people see specs such as "44% higher color saturation" or "full sRGB support", most people go "meh" - basically because most people don't know what it is. Resolution, anyone can understand, but that doesn't mean that it is more important. Color fidelity differs from resolution in one key aspect: Size doesn't matter.

    The key here is that HD video (whether it is HDTV, blu-ray, web content etc) uses the sRGB color gamut. So basically, if you want to watch HD video without any loss of fidelity, not only do you need a certain resolution, and a certain contrast, you need a certain color saturation as well. And most importantly, not just "as high as possible", but it should match the sRGB reference. Only when the display matches the color gamut of the content, do you experience the full quality of the content.

    One thing I would like to point out here is: You can scale resolution (change resolution), without actually impacting the artistic efforts of the content - you won't see as much detail, but the overall artistic impression remains. However, when you change the colors to a different gamut, the artistic impression may very well change. There is a reason that "The Matrix" has a green tinge, for example.

    When the iPad 3 came out,Displaymate basically called it a studio reference monitor. The colors are very accurate, what you will see is exactly the same colors as was chosen (!) in the studio for any given content. It's not just about seeing "good" color, or being impressed by color saturation - it's about consistency. This blog explains it well, Apple has chosen to make sRGB the standard color gamut of displays to come. This means that when you create content, whether it is web content or video, you know exactly what it will look like on any Apple device. Before, any image would look different on an iPhone compared to an iMac, for example. With the move to very accurate sRGB representation, Apple makes sure that not only does the experience match between devices, it looks the best it can be, because basically it allows the content creator to decide how it looks, it isn't up to your particular device.

    In my opinion, Apple moving to a consistent sRGB color gamut across the board, is one of the most important steps in improving the perceived image quality in the consumer marketplace. This is NOT! about Apple going their own ways, this is actually about Apple just following reference standards that has been available since the birth of HD, and is used in studios and high end home cinema gear, but it's just that most other companies in the consumer marketplace don't really care, simply because it's too complex to explain to the customers. It's easier to sell "MOAR COLLOURS!!i!" than color fidelity.

    Apple should be highly praised for bringing what is essentially studio reference quality images to a 4" phone display, instead of people bashing them for "only" having 640p resolution. Sure, you can say that it is overkill, but I don't think so - it's all about consistency.

    Oh, and by the way: IF Apple chooses to put a TV on the market, and gives it the same color fidelity that is already on the iPhone 5, the new iPad, and the Macbook Pro Retina, that would probably make it the best consumer display available at any price in this particular regard. There is very few televisions commercially available today, that matches the color fidelity of the new iPad, the Macbook Pro Regina, and presumably the iPhone 5 - and those only after careful professional calibration. If Apple puts such a display on the market, most professional calibrators will probably be put out of business. If that's not a testiment to the image quality of these displays, I don't know what is.
     
  2. THE BG 86 macrumors regular

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    Feb 14, 2008
    #2
    Well said. That was actually one of things I'm most excited about myself in the new i5
     
  3. AFDoc macrumors 68030

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  4. wongulous macrumors 6502a

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    #4
    This is so awesome. I'm excited for my super-accurate color iPhone :D great info.

    (Also, Macbook Pro Regina... made me lol and want to watch Mean Girls)
     
  5. Otto J thread starter macrumors member

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    Oct 22, 2010
    #5
    Oops! :)
     
  6. TM WAZZA macrumors 68000

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    Hamilton, New Zealand
    #6
    What happens when the OCD boys complain of Yellow hue gate, Pink hue gate and blue hue gate?
     
  7. ItalianBoston macrumors regular

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  8. iLukeJoseph macrumors 6502

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    Dec 20, 2011
    #8
    Not trying to bust your you know what's ;). But your above statement is "wrong". I think it is awesome that you are trying to educate the masses. But HD Video is Rec. 709. Yes sRGB and Rec. 709 uses the same whitepoint and color primaries, but the gamma curves differ.

    Will add more later, but to close to pre-order time :)
     
  9. Otto J thread starter macrumors member

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    Oct 22, 2010
    #9

    It is not "wrong", I just left out information... :)

    HD does use the same gamut as sRGB, which is what I stated. Gamma is heavily reluctant on ambient light, so I don't actually think that it makes any practical sense to discuss the differences between sRGB gamma and Rec.709 gamma (which isn't even properly defined) on a portable display. Most often perceived gamma will be wrong anyway, given the surroundings. Secondly, gamma is basically a choice in the software setup. Apple could if they wanted to, have different gamma for different content (i.e. one for web, one for video playback), change gamma according to ambient light (which I'm guessing they do, but I don't know), etc. However, you can't expand the color gamut in software if the hardware isn't capable. That's why this increase in hardware spec is important. Which I'm guessing you already know, I'm just trying to explain why I left that out - as you say, I'm educating masses here, so we'll need to simplify things a bit... No offence.
     
  10. jps1012 macrumors 6502a

    jps1012

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  11. greytmom macrumors 68040

    greytmom

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    Jun 23, 2010
    #11
    Your post rocks, and yep, I was excited about that during the keynote. Now I know why.
     
  12. Oppressed macrumors 65816

    Oppressed

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    Aug 15, 2010
    #12
    Very informative and helpful. One of the only useful post on these forums. This makes me appreciate the display on my iPad and new iPhone more. Thanks!
     
  13. Geckotek macrumors G3

    Geckotek

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    NYC
    #13
    Excellent post Otto. Count me as one that was impressed when I saw the specs of the new screen. :D
     

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