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.
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.