Register Guidelines E-Books Search Today's Posts Mark Forums Read

Go Back   MobileRead Forums > E-Book General > General Discussions

Notices

Reply
 
Thread Tools Search this Thread
Old 07-03-2012, 02:28 PM   #31
Ankh
Guru
Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.
 
Ankh's Avatar
 
Posts: 714
Karma: 2003751
Join Date: Oct 2008
Location: Ottawa, ON
Device: Kobo Glo HD
Quote:
Originally Posted by HarryT View Post
Rationally speaking, there should be absolutely no difference between reading from an eInk screen or reading from a backlit screen whose brightness is correctly set.

I can only think that people who complain that they can't use backlit screens perhaps have the brightness set too high?
Everything about human-machine interaction is complex, and the complexity mainly comes from the "human" side of interaction. First, every person reacts differently, and second, our eyes have a weird tendency to favour certain lightning conditions. For example, we prefer daylight to most artificial sources of lightning, regardless of the luminosity or the energy delivered in process.

I am not certain what is the exact source of problems with backlit use, it might be something as simple as refresh cycles that we don't really "see", but still can tire our eyes after prolonged use.
Ankh is offline   Reply With Quote
Old 07-03-2012, 03:47 PM   #32
HarryT
eBook Enthusiast
HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.
 
HarryT's Avatar
 
Posts: 85,544
Karma: 93383043
Join Date: Nov 2006
Location: UK
Device: Kindle Oasis 2, iPad Pro 10.5", iPhone 6
Quote:
Originally Posted by Ankh View Post
I am not certain what is the exact source of problems with backlit use, it might be something as simple as refresh cycles that we don't really "see", but still can tire our eyes after prolonged use.
LCD screens don't have "refresh cycles"; their display is constant, just like eInk, until it explicitly changes. An LCD display doesn't flicker, like a CRT does.
HarryT is offline   Reply With Quote
Advert
Old 07-03-2012, 04:45 PM   #33
Ankh
Guru
Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.Ankh ought to be getting tired of karma fortunes by now.
 
Ankh's Avatar
 
Posts: 714
Karma: 2003751
Join Date: Oct 2008
Location: Ottawa, ON
Device: Kobo Glo HD
Quote:
Originally Posted by HarryT View Post
LCD screens don't have "refresh cycles";
Are we referring to the same thing?

The decision to change a pixel (or not) still happens periodically, most of the modern OS'es will show "refresh rate" of the monitor, which is, if I am not mistaken, the mode of operation defined/limited by the panel's capabilities. Isn't the crystal "re-polarized" (gross simplification) every refresh cycle?
Ankh is offline   Reply With Quote
Old 07-04-2012, 12:12 AM   #34
piper28
Zealot
piper28 ought to be getting tired of karma fortunes by now.piper28 ought to be getting tired of karma fortunes by now.piper28 ought to be getting tired of karma fortunes by now.piper28 ought to be getting tired of karma fortunes by now.piper28 ought to be getting tired of karma fortunes by now.piper28 ought to be getting tired of karma fortunes by now.piper28 ought to be getting tired of karma fortunes by now.piper28 ought to be getting tired of karma fortunes by now.piper28 ought to be getting tired of karma fortunes by now.piper28 ought to be getting tired of karma fortunes by now.piper28 ought to be getting tired of karma fortunes by now.
 
Posts: 113
Karma: 1178328
Join Date: Feb 2011
Device: none
Quote:
Originally Posted by murraypaul View Post
I think Harry's question is: Has it been shown the using backlit displays affects sleep patterns, or has it been shown that using a display of a particular brightness affects sleep patterns? If you shone a bright enough light onto a reflective display so that the light output equaled that of the backlit display, would there be any difference?
If the study was done properly (and I haven't actually tracked it down and read it), they should have controlled for brightness levels. Based on the researchers I work with, I'll give the people that did that study the benefit of the doubt that they did unless I see otherwise. I've sat through enough talks and job talks in my department to know that someone that didn't do that would likely be skewered and roasted slowly over the coals.

Bah, now I think I'm going to have to spend some time tracking it down to read it.
piper28 is offline   Reply With Quote
Old 07-04-2012, 12:31 AM   #35
Belfaborac
Wizard
Belfaborac ought to be getting tired of karma fortunes by now.Belfaborac ought to be getting tired of karma fortunes by now.Belfaborac ought to be getting tired of karma fortunes by now.Belfaborac ought to be getting tired of karma fortunes by now.Belfaborac ought to be getting tired of karma fortunes by now.Belfaborac ought to be getting tired of karma fortunes by now.Belfaborac ought to be getting tired of karma fortunes by now.Belfaborac ought to be getting tired of karma fortunes by now.Belfaborac ought to be getting tired of karma fortunes by now.Belfaborac ought to be getting tired of karma fortunes by now.Belfaborac ought to be getting tired of karma fortunes by now.
 
Belfaborac's Avatar
 
Posts: 1,498
Karma: 5199835
Join Date: May 2010
Location: Norway
Device: Sony PRS-505, PRS-950
I think Harry very likely has hit the nail on the head with his comment on brightness. Most backlit screens are generally multi-purpose and used for instance to read comics and watch movies. Higher brightness levels make the colours "pop" and gives more life to movies and such and when the time comes to read a book how many think of adjusting the brightness?

Having said that, I think Ankh is right on the money too when (s)he (?) says that "Everything about human-machine interaction is complex". Human responses to stimuli are often inexplicable, or can only be explained partially, in scientific terms. Just visit a Hi-Fi forum sometime, to witness protracted discussions/violent arguments over which piece of cable is better suited to connect two audio components.
Belfaborac is offline   Reply With Quote
Advert
Old 07-05-2012, 01:44 AM   #36
HarryT
eBook Enthusiast
HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.
 
HarryT's Avatar
 
Posts: 85,544
Karma: 93383043
Join Date: Nov 2006
Location: UK
Device: Kindle Oasis 2, iPad Pro 10.5", iPhone 6
Quote:
Originally Posted by Ankh View Post
Are we referring to the same thing?

The decision to change a pixel (or not) still happens periodically, most of the modern OS'es will show "refresh rate" of the monitor, which is, if I am not mistaken, the mode of operation defined/limited by the panel's capabilities. Isn't the crystal "re-polarized" (gross simplification) every refresh cycle?
Yes, the display has a refresh rate, but it doesn't flicker at that rate as a CRT does. The display is flicker-free, just like eInk.
HarryT is offline   Reply With Quote
Old 07-05-2012, 11:20 AM   #37
haydnfan
Guru
haydnfan ought to be getting tired of karma fortunes by now.haydnfan ought to be getting tired of karma fortunes by now.haydnfan ought to be getting tired of karma fortunes by now.haydnfan ought to be getting tired of karma fortunes by now.haydnfan ought to be getting tired of karma fortunes by now.haydnfan ought to be getting tired of karma fortunes by now.haydnfan ought to be getting tired of karma fortunes by now.haydnfan ought to be getting tired of karma fortunes by now.haydnfan ought to be getting tired of karma fortunes by now.haydnfan ought to be getting tired of karma fortunes by now.haydnfan ought to be getting tired of karma fortunes by now.
 
Posts: 649
Karma: 5632362
Join Date: Dec 2011
Device: Kindle PW 4, Oasis 2
About flicker: wrong. Lcds do flicker, crts were more noticeable because they are interlaced displays that change their screen at 30 Hz since they have to use up half of their refresh rate changing the interlacing (and there is a slow decay inherit to the technology, plasmas also have this decay that is what makes plasmas look more crt like than lcds). Lcds refresh the screen at 60 Hz minimum. It still flickers just so fast that we can't see it.

About eye strain: this doesn't require physics. When the screen is brighter than the surrounding environment it is easier to get eye strain because it is harder to focus on something else in the room from time to time. That is why I use a backlight when I watch tv, and I use autodim on my iphone. A kindle reflects the light, and is thus always the same intensity as the rest of the room... so it is harder to get eyestrain reading on it.
haydnfan is offline   Reply With Quote
Old 07-05-2012, 11:26 AM   #38
HarryT
eBook Enthusiast
HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.
 
HarryT's Avatar
 
Posts: 85,544
Karma: 93383043
Join Date: Nov 2006
Location: UK
Device: Kindle Oasis 2, iPad Pro 10.5", iPhone 6
Quote:
Originally Posted by haydnfan View Post
About flicker: wrong. Lcds do flicker, crts were more noticeable because they are interlaced displays that change their screen at 30 Hz since they have to use up half of their refresh rate changing the interlacing (and there is a slow decay inherit to the technology, plasmas also have this decay that is what makes plasmas look more crt like than lcds). Lcds refresh the screen at 60 Hz minimum. It still flickers just so fast that we can't see it.
I'm sorry to disagree with you, but I really must. LCD screens do not flicker. They are refreshed 60x a second, yes, but there is no "decay" in light output from one refresh cycle to another. All that an LCD pixel is, in effect, is a coloured filter that allows through the (constantly illuminated) backlight that's behind the LCD. The LCD screen itself emits no light; it merely filters (and colours) the backlight.

From Wiki:

Quote:
Refresh rate or the temporal resolution of an LCD is the number of times per second in which the display draws the data it is being given. Since activated LCD pixels do not flash on/off between frames, LCD monitors exhibit no refresh-induced flicker, no matter how low the refresh rate.
(emphasis mine)
HarryT is offline   Reply With Quote
Old 07-05-2012, 12:35 PM   #39
tompe
Grand Sorcerer
tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.
 
Posts: 7,452
Karma: 7185064
Join Date: Oct 2007
Location: Linköpng, Sweden
Device: Kindle Voyage, Nexus 5, Kindle PW
Check flicker-free on Wikipedia:
Quote:
Contrary to popular belief, modern LCD monitors are not flicker free, since most of them use PWM for brightness control. As the brightness setting is lowered, the flicker becomes more noticeable, since the period when the backlight is active in each PWM duty cycle shortens. The problem is much more pronounced on modern LED backlit monitors, because LED backlight reacts faster to changes in current. Many users have reported headaches, eye strain, nausea, and other problems.
tompe is offline   Reply With Quote
Old 07-05-2012, 12:36 PM   #40
HarryT
eBook Enthusiast
HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.HarryT ought to be getting tired of karma fortunes by now.
 
HarryT's Avatar
 
Posts: 85,544
Karma: 93383043
Join Date: Nov 2006
Location: UK
Device: Kindle Oasis 2, iPad Pro 10.5", iPhone 6
Thanks, Tommy - that's very interesting, and I've learnt something new. Do you know if that same technology is used in backlit tablets, such as the iPad?
HarryT is offline   Reply With Quote
Old 07-05-2012, 12:41 PM   #41
David Munch
Scholar
David Munch ought to be getting tired of karma fortunes by now.David Munch ought to be getting tired of karma fortunes by now.David Munch ought to be getting tired of karma fortunes by now.David Munch ought to be getting tired of karma fortunes by now.David Munch ought to be getting tired of karma fortunes by now.David Munch ought to be getting tired of karma fortunes by now.David Munch ought to be getting tired of karma fortunes by now.David Munch ought to be getting tired of karma fortunes by now.David Munch ought to be getting tired of karma fortunes by now.David Munch ought to be getting tired of karma fortunes by now.David Munch ought to be getting tired of karma fortunes by now.
 
David Munch's Avatar
 
Posts: 1,008
Karma: 3999312
Join Date: Aug 2008
Location: Denmark
Device: Kobo Libra H2O + iPad Air 4
Anything with colors or pictures, the iPad.

Everything else, don't care.
David Munch is offline   Reply With Quote
Old 07-05-2012, 12:42 PM   #42
tompe
Grand Sorcerer
tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.
 
Posts: 7,452
Karma: 7185064
Join Date: Oct 2007
Location: Linköpng, Sweden
Device: Kindle Voyage, Nexus 5, Kindle PW
Quote:
Originally Posted by HarryT View Post
Thanks, Tommy - that's very interesting, and I've learnt something new. Do you know if that same technology is used in backlit tablets, such as the iPad?
No idea. This was new for me also and I learnt it while googling flicker-free earlier today. I could not find anything about tablets and phones which was what I was interested in.
tompe is offline   Reply With Quote
Old 07-07-2012, 03:50 AM   #43
idraw22
Zealot
idraw22 ought to be getting tired of karma fortunes by now.idraw22 ought to be getting tired of karma fortunes by now.idraw22 ought to be getting tired of karma fortunes by now.idraw22 ought to be getting tired of karma fortunes by now.idraw22 ought to be getting tired of karma fortunes by now.idraw22 ought to be getting tired of karma fortunes by now.idraw22 ought to be getting tired of karma fortunes by now.idraw22 ought to be getting tired of karma fortunes by now.idraw22 ought to be getting tired of karma fortunes by now.idraw22 ought to be getting tired of karma fortunes by now.idraw22 ought to be getting tired of karma fortunes by now.
 
Posts: 115
Karma: 1094380
Join Date: Dec 2009
Location: arkansas
Device: Jetbook Lite, Kindle 3, jetbook mini, sony clie, sony prs-T1
Too bright fer me...
idraw22 is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
iPad Ipad is not an ereader, the display is not for reading splendor Apple Devices 151 07-07-2019 12:29 PM
iPad Amazon’s Kindle iOS app now ready for the new iPad’s Retina*Display monkeyluis Apple Devices 9 03-18-2012 08:27 PM
Rumoured Retina Display on iPad 3 Skilgannon Apple Devices 16 03-07-2012 03:29 PM
iPad Do you think the next iPad will have a "retina display"? jibril Apple Devices 46 06-13-2010 10:10 AM


All times are GMT -4. The time now is 12:39 AM.


MobileRead.com is a privately owned, operated and funded community.