Heavy ghosting watching comics

flowoeB · 03-26-2009, 09:50 AM

hi!

For testing I scanned a view pages of a comic (sin city) in black and white and put them on my dr1000:

after a reset of the device the pages show up close to perfect - very crisp. after a view page turns the display starts ghosting. this gets worse with every turn. it does'nt get better closing and reopening the file, nor doubletapping the system menu to refresh the screen.

after reseting the device the ghosting is much better but then starts to get worse after a view pageturns...

any suggestions? is there any way to 'calibrate' the display as it seams to be done at startup while the reader is running? any hidden settings somewhere?

(sorry, can't upload the pics because of copyright)

myprecious · 03-26-2009, 10:04 AM

You've got nothing but trouble with your device - send it to Irex and have it fixed.

flowoeB · 03-26-2009, 10:33 AM

this is not a real problem for me - don't have the time to read comics anyway

but i realised the effect reading text too (you realy have too look very close to see it) so i tried to test it. now I'm curious if this is reproduceable on other DR and if there's a way arround it.
all other problems i had were somehow 'fixable' - even reading ePub with DRM on the DR so i still don't believe that my reader has some kind of a hardware issue...

Shaggy · 03-26-2009, 10:44 AM

You do know that some ghosting with eInk is normal?

flowoeB · 03-26-2009, 11:33 AM

@Shaggy: yes, i do, but is it normal that it gets worse with longer runningtime and much better after a reset? is it possible that the DR does 'calibrate' the display at startup or some kind of 'erase' it at a higher power level?

Shaggy · 03-26-2009, 12:13 PM

Quote:

Originally Posted by flowoeB

is it possible that the DR does 'calibrate' the display at startup or some kind of 'erase' it at a higher power level?

That's not how it works.

Grimulkan · 03-26-2009, 12:25 PM

I don't really know if the trouble you are having is exceptionally bad, but a small amount of ghosting is expected. Could you post screenshots with ghosting using non-copyrighted images?

I have noticed enough ghosting to bother me while reading comics as well, but I don't know if this is normal for all e-ink displays or a software bug in the DR controller. Theoretically, a "full refresh" (when all "pixels" on the screen are inverted and brought to a new state) should minimize ghosting, but I often find that the traces of the menu I brought up remains even after a refresh. This is why I would love to see a "ghostbuster" button, thant refreshed the screen (multiple times, if necessary) in such a way that no ghosts remain

Quote:

Originally Posted by flowoeB

@Shaggy: yes, i do, but is it normal that it gets worse with longer runningtime and much better after a reset? is it possible that the DR does 'calibrate' the display at startup or some kind of 'erase' it at a higher power level?

Something does happen at startup. I have experienced the issues described in this post, which may be relevant.

From the post:

Quote:

Originally Posted by allovertheglobe

<snip>
Usually a reset (not shutdown/restart) fixes the issue. To me it seems that the display controller switches the table it uses to look up the values of the 16 supported gray tones, or at least something related. I would think that if was eInk-related, it would be more permanent or would take longer to revert than instantly switching back to normal after a reset.

I've also noticed that drawing something deep black and then having something lighter appear in that same spot without a full screen refresh makes the color lighter than it should be (seen when hitting the "shift" key on my updated matchbox keyboard).

flowoeB · 03-26-2009, 12:40 PM

@Grimulkan it's exactly how you describe it. My english sometimes isn't good enough to write what I'd like to write

and yes - it really could be the same issue as described in the link that you posted! thx for finding it!

Grimulkan · 03-26-2009, 12:47 PM

I just took a look at a few Sin City comics. You're absolutely right, the ghosting is particularly bad

A screen refresh by toggling the menu gets rid of all the "old ghosts", but adds new ones. This particular comic has lots of large patches of deep black and white, which seems to aggravate the issue.

I'll try this on the Sony PRS-505 and update, to confirm that this a DR-specific issue.

flowoeB · 03-26-2009, 12:49 PM

@Shaggy: do you have any idea why the reset makes things better? what happens when the reader inits the display and what is the diffrence to what it does while a page turn?

the sony 505 has a trim-pot to set contrast - the higher the contrast the more ghosting you get - is there something like it on the DR1000S and can it be that it is controlled via software?

Grimulkan · 03-26-2009, 12:57 PM

Quote:

Originally Posted by flowoeB

<snip>
the sony 505 has a trim-pot to set contrast - the higher the contrast the more ghosting you get...

It does!? The DR does not do this with the current firmware AFAIK, but I've noticed a low level command in the code that changes a certain voltage level. No idea if I want to play with it, or if it even works.

Could anyone with knowledge of the physics of e-ink explain the trade-off between higher contrast and ghosting (or point me to a resource)?

flowoeB · 03-26-2009, 01:03 PM

http://www.msh-tools.com/ebook/contrast.html

I didn't see the 505 board but I heard it has the trim-pot too

Shaggy · 03-26-2009, 01:46 PM

Quote:

Originally Posted by Grimulkan

I don't really know if the trouble you are having is exceptionally bad, but a small amount of ghosting is expected. Could you post screenshots with ghosting using non-copyrighted images?

It probably has to do with the amount of "coverage" of the content on the screen. Images/comics will probably show more ghosting than text because they're "activating" a lot more of the black eInk. It also helps with text that typically the lines of text appear on top of each other when you refresh. IE, if the book is formatted (font size, etc) with 30 lines of text on the screen, each time you refresh the lines are in the same spot, so you don't notice the ghosting as much.

When I'm reading ebooks, I don't really notice the ghosting at all, but when I get to a blank screen (end of chapter, etc) or turn the device off, I can see ghosting in bands across the screen where the lines of text were.

Pages of images/comics may show the ghosting more because there's less overlap of the content. IE, a spot on the screen that is dark on one page may be light on the next, etc.

Shaggy · 03-26-2009, 01:57 PM

Typically, you control the ghosting in the way that you do screen refreshes. Most of the time, when you change from one page to another, there isn't just a single refresh. Depending on the device, they'll either refresh to a solid black screen first, or an inverse of the current screen, and then quickly refresh again to the next page. It's a multiple step process. There's a trade off between how long it takes to do the page turn process versus how much ghosting you get. The more of those refreshes it does, the more it'll clean up any ghosting artifacts.

The difference between a reset/boot and just a normal page turn is that it's probably doing several of those refreshes versus just a single one.

The other component are the waveforms that the display controller uses to drive the screen, but that's usually hard coded in the firmware. Again though, it's an optimization between contrast vs ghosting. iRex has tweaked them over time via firmware upates, but I'm not aware of any options for the user to select a different one.

Shaggy · 03-26-2009, 01:58 PM

Quote:

Originally Posted by Grimulkan

Something does happen at startup. I have experienced the issues described in this post, which may be relevant.

I think that's a separate issue from ghosting.

03-26-2009, 09:50 AM	#1
flowoeB E-Reader Sammler Posts: 134 Karma: 1000 Join Date: Feb 2009 Location: Austria Device: plenty...	Heavy ghosting watching comics hi! For testing I scanned a view pages of a comic (sin city) in black and white and put them on my dr1000: after a reset of the device the pages show up close to perfect - very crisp. after a view page turns the display starts ghosting. this gets worse with every turn. it does'nt get better closing and reopening the file, nor doubletapping the system menu to refresh the screen. after reseting the device the ghosting is much better but then starts to get worse after a view pageturns... any suggestions? is there any way to 'calibrate' the display as it seams to be done at startup while the reader is running? any hidden settings somewhere? (sorry, can't upload the pics because of copyright)

03-26-2009, 12:40 PM	#8
flowoeB E-Reader Sammler Posts: 134 Karma: 1000 Join Date: Feb 2009 Location: Austria Device: plenty...	@Grimulkan it's exactly how you describe it. My english sometimes isn't good enough to write what I'd like to write and yes - it really could be the same issue as described in the link that you posted! thx for finding it! Last edited by flowoeB; 03-26-2009 at 12:43 PM.

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03-26-2009, 10:04 AM	#2
myprecious Zealot Posts: 100 Karma: 28 Join Date: Mar 2009 Location: Nowy Targ, Poland Device: DR1000S	You've got nothing but trouble with your device - send it to Irex and have it fixed.

03-26-2009, 10:33 AM	#3
flowoeB E-Reader Sammler Posts: 134 Karma: 1000 Join Date: Feb 2009 Location: Austria Device: plenty...	this is not a real problem for me - don't have the time to read comics anyway but i realised the effect reading text too (you realy have too look very close to see it) so i tried to test it. now I'm curious if this is reproduceable on other DR and if there's a way arround it. all other problems i had were somehow 'fixable' - even reading ePub with DRM on the DR so i still don't believe that my reader has some kind of a hardware issue...

03-26-2009, 10:44 AM	#4
Shaggy Wizard Posts: 4,293 Karma: 529619 Join Date: May 2007 Device: iRex iLiad, DR800SG	You do know that some ghosting with eInk is normal?

03-26-2009, 11:33 AM	#5
flowoeB E-Reader Sammler Posts: 134 Karma: 1000 Join Date: Feb 2009 Location: Austria Device: plenty...	@Shaggy: yes, i do, but is it normal that it gets worse with longer runningtime and much better after a reset? is it possible that the DR does 'calibrate' the display at startup or some kind of 'erase' it at a higher power level?

03-26-2009, 12:47 PM	#9
Grimulkan Lord Posts: 177 Karma: 328 Join Date: Feb 2009 Device: Q1 (on way out), PRS505, DR1000S (dead :<), TC1100 (10'' perfection!)	I just took a look at a few Sin City comics. You're absolutely right, the ghosting is particularly bad A screen refresh by toggling the menu gets rid of all the "old ghosts", but adds new ones. This particular comic has lots of large patches of deep black and white, which seems to aggravate the issue. I'll try this on the Sony PRS-505 and update, to confirm that this a DR-specific issue.

03-26-2009, 12:49 PM	#10
flowoeB E-Reader Sammler Posts: 134 Karma: 1000 Join Date: Feb 2009 Location: Austria Device: plenty...	@Shaggy: do you have any idea why the reset makes things better? what happens when the reader inits the display and what is the diffrence to what it does while a page turn? the sony 505 has a trim-pot to set contrast - the higher the contrast the more ghosting you get - is there something like it on the DR1000S and can it be that it is controlled via software?

03-26-2009, 01:03 PM	#12
flowoeB E-Reader Sammler Posts: 134 Karma: 1000 Join Date: Feb 2009 Location: Austria Device: plenty...	http://www.msh-tools.com/ebook/contrast.html I didn't see the 505 board but I heard it has the trim-pot too

03-26-2009, 01:57 PM	#14
Shaggy Wizard Posts: 4,293 Karma: 529619 Join Date: May 2007 Device: iRex iLiad, DR800SG	Typically, you control the ghosting in the way that you do screen refreshes. Most of the time, when you change from one page to another, there isn't just a single refresh. Depending on the device, they'll either refresh to a solid black screen first, or an inverse of the current screen, and then quickly refresh again to the next page. It's a multiple step process. There's a trade off between how long it takes to do the page turn process versus how much ghosting you get. The more of those refreshes it does, the more it'll clean up any ghosting artifacts. The difference between a reset/boot and just a normal page turn is that it's probably doing several of those refreshes versus just a single one. The other component are the waveforms that the display controller uses to drive the screen, but that's usually hard coded in the firmware. Again though, it's an optimization between contrast vs ghosting. iRex has tweaked them over time via firmware upates, but I'm not aware of any options for the user to select a different one.

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