Mobileread
What does Grey Level(Scale) mean
#1  droople 03-09-2010, 03:19 AM
Hi All

I'm just bought Nook, which on the wiki says it has 16bit grey levels.

http://wiki.mobileread.com/wiki/Nook

I put some image pdf into it, and found that the images have very obvious boards between the colours.

Which looks like this image:
http://en.wikipedia.org/wiki/File:Parrot_EGA_monochrome_palette.png

If the Grey level for ebook device is the same definition as the wiki
http://en.wikipedia.org/wiki/Grayscale

16bit should be enough for a picture, or 16 level means 4bit (16 levels of grey)?

Cheers
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#2  pauli 03-09-2010, 03:29 AM
it just says 16 levels of grey, not 16 bit. 16 levels of grey are enough to display pictures if properly dithered.
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#3  wallcraft 03-09-2010, 06:34 AM
For a good example of what can happen with gray scales, see More display issues on the DR. It sounds like the Nook might not be doing any dithering, which is marginally acceptable with 16 gray levels.
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#4  applechutney 03-10-2010, 03:52 AM
Quote droople
Hi All

I'm just bought Nook, which on the wiki says it has 16bit grey levels.

http://wiki.mobileread.com/wiki/Nook

I put some image pdf into it, and found that the images have very obvious boards between the colours.

Which looks like this image:
http://en.wikipedia.org/wiki/File:Parrot_EGA_monochrome_palette.png

If the Grey level for ebook device is the same definition as the wiki
http://en.wikipedia.org/wiki/Grayscale

16bit should be enough for a picture, or 16 level means 4bit (16 levels of grey)?

Cheers
Hi,

It is actually 16 levels of Gray (4 bit).

Typically,
Text is displayed using 4 levels of gray.
Menu items & icons using 8 levels of gray.
Images are displayed using 16 levels of gray.

I have posted an image here...
(http://www.flickr.com/photos/8788289@N08/4422160802/)
image »


best wishes
aPpLe ChUtNeY.
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#5  droople 03-12-2010, 06:15 PM
Thank you guys~~
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#6  andrys 03-12-2010, 08:32 PM
I did a blog article on this when the Kindle first went to the 16 levels of gray and what that meant vs 4 and 8 levels as far as potential.

It's at http://bit.ly/4vs16grays
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