Interesting experiment with temperatures and screen contrast

Sunspark · 03-27-2010, 12:38 AM

E-Ink apparently is quite sensitive to temperature and this can affect contrast. How much I hadn't realized until today. I was walking to my car in freezing weather and reading as I went (why not). I had noticed the edges of the screen fading out slightly before and wasn't sure what the cause was, but as I continued it faded more and more and I knew then that it was temperature related.

Basically the colder it gets the darker and cloudier the screen gets including white ghosting of letters from the previous page and the letters get very faded out (gray). Be careful, because apparently the specification of e-ink is 0 to 35 C.

Now here's something interesting. If I laid my finger across the cold screen, and then did a page turn, all areas surrounding it would be pale and clouded except the area under my finger.. which would have a white background and actual BLACK letters. The black letters weren't light related either, because it's been sitting here for a few hours indoors and under incandescent light you can clearly see that they're black letters.

Did a page turn just now, and whoosh, letters reverted back to their usual lower contrast medium to dark gray.

I wonder if it's even possible somehow in software to get it to do this more often. But these were unquestionably dark black letters in the times font just like an actual book.

Decided to try an experiment.. held the screen over an incandescent lightbulb for a few seconds.

A bit blacker letters.

So in conclusion, these screens are calibrated for the tropics not North America and you will get the best results during the summertime.

conundrum · 03-27-2010, 08:45 AM

interesting...

you just know what the next hack will be, e-reader internal heater sheet.

I had noticed this with my '600 but it is delayed somewhat as the screen is covered with a touchscreen glass.

hidari · 03-27-2010, 07:32 PM

I found for transporting ebook readers in cold weather (-3 to -11 Celcius) is not bad at all. I read outside time to time in winter but not long enough to have the PP slow down. I bike with my PP all winter, so it is in cold weather (in my bag) for up to 3 hours a day. Never had a problem. Then again it does not get below minus 15 Celcius here. When I lived in Moscow, I would have had regular probs with an eink reader. but I had a PDA back then..... and no problems even at minus 25...

AlexGrant · 03-28-2010, 04:22 PM

The best usage for e-book reader is on a sunny beach where notebook screen does not produce a good visible image. I do not care about winter. I want e-book reader work on direct sunlight in Cancun, Mexico.

theducks · 03-28-2010, 09:56 PM

Quote:

Originally Posted by AlexGrant

The best usage for e-book reader is on a sunny beach where notebook screen does not produce a good visible image. I do not care about winter. I want e-book reader work on direct sunlight in Cancun, Mexico.

No problem. I read in the Lounge chair in my yard all the time.

Just keep it out of the salt water and Margaritas

Robertb · 03-29-2010, 01:13 PM

Dear All:

The EZ Reader and Pocket PRO are made by the factory in China. As you know, the area around Shanghai can get very, very hot. That may or may not explain why severe cold might effect the screen. The panels (screens with E-INK) are made in Taiwan... also very hot.

I would not recommend reading your Pocket PRO while snowboarding!!

theducks · 03-29-2010, 01:31 PM

Quote:

Originally Posted by Robertb

Dear All:

The EZ Reader and Pocket PRO are made by the factory in China. As you know, the area around Shanghai can get very, very hot. That may or may not explain why severe cold might effect the screen. The panels (screens with E-INK) are made in Taiwan... also very hot.

I would not recommend reading your Pocket PRO while snowboarding!!

But the Mammoth Mountain PDF slope map will display on the PEz

jess4276 · 04-01-2010, 09:36 PM

A friend of mine has the Opus and she reads in the morning at the bus stop. While it was still cold here in Pittsburgh, she was telling me how as her machine got colder the screen not only got lighter but the page turns took longer until it would freeze up on her. I think it's probably a combination of the screen technology and battery since cold temps discharge batteries. I don't think it's just a Pocket Pro issue.

03-27-2010, 12:38 AM	#1
Sunspark Zealot Posts: 122 Karma: 2600 Join Date: Sep 2009 Device: EZ Reader Pocket PRO	Interesting experiment with temperatures and screen contrast E-Ink apparently is quite sensitive to temperature and this can affect contrast. How much I hadn't realized until today. I was walking to my car in freezing weather and reading as I went (why not). I had noticed the edges of the screen fading out slightly before and wasn't sure what the cause was, but as I continued it faded more and more and I knew then that it was temperature related. Basically the colder it gets the darker and cloudier the screen gets including white ghosting of letters from the previous page and the letters get very faded out (gray). Be careful, because apparently the specification of e-ink is 0 to 35 C. Now here's something interesting. If I laid my finger across the cold screen, and then did a page turn, all areas surrounding it would be pale and clouded except the area under my finger.. which would have a white background and actual BLACK letters. The black letters weren't light related either, because it's been sitting here for a few hours indoors and under incandescent light you can clearly see that they're black letters. Did a page turn just now, and whoosh, letters reverted back to their usual lower contrast medium to dark gray. I wonder if it's even possible somehow in software to get it to do this more often. But these were unquestionably dark black letters in the times font just like an actual book. Decided to try an experiment.. held the screen over an incandescent lightbulb for a few seconds. A bit blacker letters. So in conclusion, these screens are calibrated for the tropics not North America and you will get the best results during the summertime.

03-29-2010, 01:13 PM	#6
Robertb Astak Director, Bus. Devl Posts: 2,560 Karma: 2500000 Join Date: Apr 2008 Device: Astak Pocket PRO	Made in China so HOT is norm Dear All: The EZ Reader and Pocket PRO are made by the factory in China. As you know, the area around Shanghai can get very, very hot. That may or may not explain why severe cold might effect the screen. The panels (screens with E-INK) are made in Taiwan... also very hot. I would not recommend reading your Pocket PRO while snowboarding!!

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03-27-2010, 08:45 AM	#2
conundrum Enthusiast Posts: 42 Karma: 22 Join Date: Dec 2009 Location: guernsey Device: prs-600	interesting... you just know what the next hack will be, e-reader internal heater sheet. I had noticed this with my '600 but it is delayed somewhat as the screen is covered with a touchscreen glass.

03-27-2010, 07:32 PM	#3
hidari MR Drone Posts: 1,613 Karma: 15612282 Join Date: Oct 2007 Location: DRONEZONE Device: PB360+, Huawei MP5, Libra H20	I found for transporting ebook readers in cold weather (-3 to -11 Celcius) is not bad at all. I read outside time to time in winter but not long enough to have the PP slow down. I bike with my PP all winter, so it is in cold weather (in my bag) for up to 3 hours a day. Never had a problem. Then again it does not get below minus 15 Celcius here. When I lived in Moscow, I would have had regular probs with an eink reader. but I had a PDA back then..... and no problems even at minus 25...

03-28-2010, 04:22 PM	#4
AlexGrant Electronic R&D Engineer Posts: 22 Karma: 10 Join Date: Feb 2010 Location: Atlanta, USA Device: Astak Pocket PRO 5"	The best usage for e-book reader is on a sunny beach where notebook screen does not produce a good visible image. I do not care about winter. I want e-book reader work on direct sunlight in Cancun, Mexico.

04-01-2010, 09:36 PM	#8
jess4276 Member Posts: 13 Karma: 10 Join Date: Nov 2009 Device: Astak Pocket Pro Maroon	A friend of mine has the Opus and she reads in the morning at the bus stop. While it was still cold here in Pittsburgh, she was telling me how as her machine got colder the screen not only got lighter but the page turns took longer until it would freeze up on her. I think it's probably a combination of the screen technology and battery since cold temps discharge batteries. I don't think it's just a Pocket Pro issue.

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