Display Bit-Depth and App Differences

Display Bit-Depth and App Differences

I just posted my newest entry in the Sketches project titled Fog in the Hills and Aits. As I hope is obvious, this project consists of images of fog in the hills and fog in the aits — and as any of you know who have produced fog pictures, they often consist of very graduated tonal scales that put digital imaging bit depths to the test. As a part of my normal proofing routine, I open the PDF in my iPad using GoodReader and was pleased to see smooth graduations in the high-key tones in the fog. I popped over to the Google Nexus 7 and opened the PDF in the Mantano Reader, the app we've been recommending for some time. Horror of horrors, the smooth graduations in the fog tones were blocky, banded, and looked absolutely horrible (below left). I cringed. Is it possible that Google Nexus 7 display is limited to a 16-bit display? In order to test this, I open the same PDF using the Adobe Kindle Reader app. To my relief, the display looked fantastic — smooth tones the way they should look in a 32-bit display rendition.

Mantano Reader

Kindle Reader app

Evidently different apps will render images with different bit depths, regardless of the potential bit depth for the device. Who knew? Shame on any programmer who would render PDFs in anything less than full bit depth potential of the display device. Perhaps they assume that anyone viewing PDFs is viewing office documents only, but what an awful mistake in judgment that is.

Notice the color differences, too. Obviously one program is using the embedded color profile, the other is not. Guess which is. Hint: here is a screen capture from my calibrated desktop computer using Adobe Reader to render the same PDF.

So, I guess the advice is to be careful which app you're using, especially if the images are banding and appear compromised. It may be that simply changing the viewing app will solve the problem and provide you with the intended viewing experience.

Comments

[Dave Kosiur]

In some ways, it's not surprising ... remember all the problems we had with web browsers ignoring embedded color profiles in images? I'm convinced that these problems are mainly due to two issues: (1) sloppiness on the part of the programmer(s); and (2) dealing with the amount of RAM available for apps on a tablet (and 8-bit image requires far less to display than a 16-bit image).

Just my $0.02.

[George]

Brooks, I read your article about the Nexus 7, but based on longer-time usage, would you say that it’s a good choice for looking at photographs? An article that cites a technical report claims that “images on the Nexus 7 are noticeably washed out, missing highlights, suffering from reduced image contrast, and weak colors”:

http://www.zdnet.com/google-nexus-7-bright-image-compression-blamed-on-oem-incompetence-7000001450/

[Brooks]

There is no doubt that the Achilles heel of portable devices is their lack of any sort of calibration. In the several I've owned, they are all different. The iPad 1 I still use is definitely a bit on the blue side and quite light. I have to turn it down to keep the shine to a comfortable eyeball level. The Nexus 7 is a bit on the yellow side of neutral and I agree that the Zone 8 tones are pushed up to 8.5. Mid-tones look right, but the highest of highlights do seem a bit light, but not the Zone 3-5 tones. The Kindle Fire is very warm — as thought someone turned the white balance to incandescent bulbs. The ASUS Transformer is the closest to a neutral color, but if anything dumps the shadow detail more than I'd like. Nothing is as good as my hardware calibrated computer monitor. Even that, however, is different than viewing a print.

Now, having said all of that after viewing my tablet devices side by side with a photographer's critical eye, I am perfectly happy using any of them to view photographs. The eye adapts; the eye adapts; the eye adapts. All of them provide a very nice experience of viewing a well-executed photo-based publication. What color or gamma-balance shifts there are from "perfection" to implementation are — IMHO — not a deal breaker. If the photography is boring, they'll still look that way on any display. If the photography/publication is exciting, it will still look that way on any display. Not perfect, maybe not exactly like us critical photographers with exacting and discriminating eyes might like, but still exciting.

Besides, remember that anyone seeing your work on their device does not have your original digital image or print to compare it to.

Finally, when I listen to Dianna Krall on my car stereo, I have no doubt it doesn't sound like it did to her or her sound engineer when they were doing the final mix in the studio. Nonetheless, I still enjoy her music and my ear adapts for the environment in which I'm listening.

[George]

Thanks for the informative and thoughtful reply.