Color Analysis of the iPad Mini and Retina iPad Mini

Note: I am republishing this article, as it pertains equally to the new Retina Display iPad Mini, which shares similar screen color with the non-Retina version.

Characteristics of the Fourth Generation iPad with Retina Display

There are not too many surprises with the fourth generation full size iPad (wouldn’t it be great if Apple gave these products functional names?). Its largely a refresh for the sake of updating the processor and moving the connector system to the new Lightning Connector. Both worthwhile improvements, but not anything to concern us here. Still, there are more questions to be considered with the new iPad mini.

Characteristics of the iPad mini

The screen of the iPad mini offers the pixel-count of the pre-Retina iPads, in a smaller form factor. Not retina resolution, but somewhere in between the non-Retina full size iPads, and the Retina versions, by way of its decreased screen size. Many will choose to live with this enhanced, but not “Retinaed” resolution (yes, I just turned Retina into a verb) in return for the convenience of the smaller form factor and the lower price of the new mini. But what about its color characteristics for serious uses? Has Apple taken a step backwards there as well, in order to make the new mini more cost competitive in its (already populated) size range?

Earlier Testing

The answer is yes, and no. As we know from previous testing, the Retina iPad screens (and the iPhone 5 Retina screen as well) have been updated from the earlier, twisted, sub-sRGB color space of early iOS devices, to a color space very close to sRGB. The gamut plot below shows the iPad 3, with sRGB overlaid, as that order provides the clearest indication of their match.  The green primary of the iPad 3 actually exceeds sRGB by a bit, but overall this is a great match.

sRGB gamut over iPad3 gamut

We have also studied the gamut of earlier iOS devices, and seen how this gamut effects their display of web images (in sRGB) and web videos in Rec-709, which shares a number of key characteristics with sRGB. The image below is the second generation iPad, overlaid on the third generation iPad, showing the smaller and twisted gamut of the earlier screens. There is no doubt that the color accuracy of the sRGB-sized recent devices is superior to the older devices.

iPad2 gamut over iPad3 gamut

Color of the iPad mini

With that background information in mind, lets look at the gamut of the iPad mini in relation to sRGB. First, its important to note that the white point (global color tone) of the iPad mini is close to the target value of 6500K, and the gamma (ramp from black to white) is very close to the target value of Gamma 2.2. In the image below, you will recognize the earlier, sub-sRGB gamut, and twisted primaries, with the added twist of primary green, and well as primary blue, being offset sufficiently from the sRGB primaries to lie outside of sRGB, making color correction that much more difficult.

iPad mini gamut in blue, compared to sRGB in red

Conclusion

Yes, this gamut looks quite familiar, as you can see by comparing it to the previous illustrations. The iPad mini does indeed revert to the smaller, twisted shape of the earlier iOS gamut. Apple seldom takes a step backward in their relentless move forward, but here we have one example of it. So, if you were considering getting an iPad mini for use as a photo or video portfolio, please note that these color deficiencies will effect your results.

It is quite likely that in the next generation of iPad mini, Apple will move the device forward to a full sRGB gamut (and who knows, perhaps Retina resolution as well). So at this time the larger gen 3 and gen 4 iPads are the optimal iPads for display of critical color. It is possible to color calibrate the iPad mini with Datacolor’s SpyderGallery application, to produce corrected color (within the limits of the reduced gamut) in the Gallery viewer, or in other Apps if you launder your images through SpyderGallery. But for color critical uses, it may be worth holding off for a generation, to see what Apple has up its sleeve next time for the iPad mini.

Credits: C. David Tobie, Copyright 2013.   Website: CDTobie.com   Return to Blog’s Main Page

Advertisements

Color Analysis of the iPad mini

Note: I am republishing this article, as it pertains equally to the new Retina Display iPad Mini, which shares similar screen color with the non-Retina version.

Characteristics of the Fourth Generation iPad with Retina Display

There are not too many surprises with the fourth generation full size iPad (wouldn’t it be great if Apple gave these products functional names?). Its largely a refresh for the sake of updating the processor and moving the connector system to the new Lightning Connector. Both worthwhile improvements, but not anything to concern us here. Still, there are more questions to be considered with the new iPad mini.

Characteristics of the iPad mini

The screen of the iPad mini offers the pixel-count of the pre-Retina iPads, in a smaller form factor. Not retina resolution, but somewhere in between the non-Retina full size iPads, and the Retina versions, by way of its decreased screen size. Many will choose to live with this enhanced, but not “Retinaed” resolution (yes, I just turned Retina into a verb) in return for the convenience of the smaller form factor and the lower price of the new mini. But what about its color characteristics for serious uses? Has Apple taken a step backwards there as well, in order to make the new mini more cost competitive in its (already populated) size range?

Earlier Testing

The answer is yes, and no. As we know from previous testing, the Retina iPad screens (and the iPhone 5 Retina screen as well) have been updated from the earlier, twisted, sub-sRGB color space of early iOS devices, to a color space very close to sRGB. The gamut plot below shows the iPad 3, with sRGB overlaid, as that order provides the clearest indication of their match.  The green primary of the iPad 3 actually exceeds sRGB by a bit, but overall this is a great match.

sRGB gamut over iPad3 gamut

We have also studied the gamut of earlier iOS devices, and seen how this gamut effects their display of web images (in sRGB) and web videos in Rec-709, which shares a number of key characteristics with sRGB. The image below is the second generation iPad, overlaid on the third generation iPad, showing the smaller and twisted gamut of the earlier screens. There is no doubt that the color accuracy of the sRGB-sized recent devices is superior to the older devices.

iPad2 gamut over iPad3 gamut

Color of the iPad mini

With that background information in mind, lets look at the gamut of the iPad mini in relation to sRGB. First, its important to note that the white point (global color tone) of the iPad mini is close to the target value of 6500K, and the gamma (ramp from black to white) is very close to the target value of Gamma 2.2. In the image below, you will recognize the earlier, sub-sRGB gamut, and twisted primaries, with the added twist of primary green, and well as primary blue, being offset sufficiently from the sRGB primaries to lie outside of sRGB, making color correction that much more difficult.

iPad mini gamut in blue, compared to sRGB in red

Conclusion

Yes, this gamut looks quite familiar, as you can see by comparing it to the previous illustrations. The iPad mini does indeed revert to the smaller, twisted shape of the earlier iOS gamut. Apple seldom takes a step backward in their relentless move forward, but here we have one example of it. So, if you were considering getting an iPad mini for use as a photo or video portfolio, please note that these color deficiencies will effect your results.

It is quite likely that in the next generation of iPad mini, Apple will move the device forward to a full sRGB gamut (and who knows, perhaps Retina resolution as well). So at this time the larger gen 3 and gen 4 iPads are the optimal iPads for display of critical color. It is possible to color calibrate the iPad mini with Datacolor’s SpyderGallery application, to produce corrected color (within the limits of the reduced gamut) in the Gallery viewer, or in other Apps if you launder your images through SpyderGallery. But for color critical uses, it may be worth holding off for a generation, to see what Apple has up its sleeve next time for the iPad mini.

Credits: C. David Tobie, Copyright 2012.   Website: CDTobie.com   Return to Blog’s Main Page

Review and Sample Images: iOS Photography App “Rays”

Digital Film Tools iOS App “Rays” is currently available as a free download. But even at its usual price of ninety nine cents, its a bargain. Rays is one of those “one trick pony” Apps, that does one thing, but does it well. Its one trick is to add convincing rays of light to your images.

Rays allows you to choose the source location for your radiating rays of light; the only limitation being that the source location must be within the image, when in some cases you might prefer it to be outside the image. There are controls for the color of your light, the length of the rays, and the intensity of the effect versus the image you are applying it to.

Here are answers to the most likely questions about Rays:

Yes, its fun. Yes, its effective. Yes the effect is quite variable. Yes, the controls are reasonably intuitive. And yes, it runs on both the iPhone and the iPad, meaning you can work on your iPhone images right on the phone, and those or other images after sending them to the iPad (in addition to photos shot with the iPad, for those who do that). I’ve been saving the big one for last: Yes, the effects can be appropriate to advanced, or even professional imaging.

Lets look at a few sample images to get a sense of just how the Rays effect can be used. A few comments on process in advance: A couple of these images were shot with LensBaby lenses; LensBaby selective focus images lend themselves to Rays effects. Some of these images have been run through NIK SnapSeed before Rays was used on them. Thats  not unusual; multiple iOS Apps are often used in the pursuit of the best mobile images. And all of these images were checked for color and sharpness in Datacolor’s SpyderGallery after they were completed. There are other Apps that will allow you to zoom in far enough to check the sharpness, but only SpyderGallery will allow you to see a color managed view of your iOS images. I do both in SpyderGallery as it saves a step.

Lets get the obvious out of the way first: yes, you can add a halo, or aurora to a person, place, or thing with Rays. Buddha seemed like a reasonable choice, so here’s an example of the most blatant use of Rays. This is not an effect I envision myself using too often. Using it with backlit trees, as in the background of this image, could be a more realistic effect.

This second example is only a bit more subtle. Rays can be used to create a focal point within an image. If the image has motion blur, focal plane blur, or both, the effects blend nicely, and even create more sharpness in a blurred image that may not be quite sharp enough without it.

This third example uses a light source within the image as a point source for the rays. By matching the tint of the rays to the color of the light source, this can be quite realistic. Moving the source location around allows fine tuning of the rays that are created, allowing you to choose a particularly effective set of rays and shadows. Images which lack a clear focal point can be strengthened by this technique. Keep in mind that, as with other iOS imaging apps, its possible to run your image through Rays more than once. So if you feel that a second source location could improve the effect, try a second pass to find out.

Next comes the use of rays with a source outside the image. Here it would have been ideal to place the source location below the bottom of the image, to more closely align with the actual light source. Short of creating a copy of the image with extra white space at the bottom, generating the desired rays, and than cropping back to the original image size, this would not be possible. I compromised on a source location at the bottom edge of the image.

And finally, here is a macro image, where the Rays effect emulates radial lens blur. Especially with LensBaby macros, this can be quite convincing.

The effects in these images run from much more blatant in the first examples, to much more subtle, or at least more realistic, in the latter ones. Like makeup, perhaps the best Rays effect is the one your viewer never realizes is an effect at all…

Credits: C. David Tobie, Copyright 2012. Website: CDTobie.com Return to Blog’s Main Page