View Full Version : What does Grey Level(Scale) mean


droople
03-09-2010, 04:19 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

pauli
03-09-2010, 04:29 AM
it just says 16 levels of grey, not 16 bit. 16 levels of grey are enough to display pictures if properly dithered.

wallcraft
03-09-2010, 07:34 AM
For a good example of what can happen with gray scales, see More display issues on the DR (http://www.mobileread.com/forums/showthread.php?t=43021). It sounds like the Nook might not be doing any dithering, which is marginally acceptable with 16 gray levels.

applechutney
03-10-2010, 04:52 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
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/)
http://www.flickr.com/photos/8788289@N08/4422160802/


best wishes
aPpLe ChUtNeY.

droople
03-12-2010, 07:15 PM
Thank you guys~~

andrys
03-12-2010, 09:32 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