Tuesday, 23 January 2018

Something About Blue Light; and Reading Habits

Not long ago, fellow blogger Nan wrote here about reading from a kindle (or other e-reader) vs. from a printed book, and about how she feels she takes up less information from the former than from the latter.

I read that post while I was away from home and did not have the opportunity to comment then. Also, there is rather a lot I want to say about the subject, more than what would have been appropriate in a comment.

One point in Nan's post was (not her own point, but quoted from a book) that
"if we use an e-reader or a laptop before going to sleep, our brains are affected so that we are more likely to sleep badly. It is something to do with blue light." 

Before you read on, let me emphasise that the following are first and foremost my own thoughts and my own opinion, based on my personal experience. I am not a neuro-biologist and have never been to university. But I have read a few books and many articles about neurobiology and how our brain works (as far as scientists understand it), and am paraphrasing that information.

My thoughts on the topic:

What does bother our brains is not so much the blue light as the frequency with which a lit-up screen is refreshed (the refresh rate; see wikipedia for more info). If you look at the settings of your desktop PC, you will probably find where you can adjust the refresh rate (measured in Hz). Few people feel the need to change the default setting, but the option is usually there for every screen.

The same is true for any other screen with back lights, such as smartphones, tablets, and the new generation e-readers. Even though you can not consciously see the "flickering" that comes from those lights (and refreshing), your optical nerves register it and send it to your brain. This makes your mind tire a lot more quickly as if you were reading from an "immobile", static source such as a sheet of paper. Then, it is your eyes that do the moving, not the reading material itself.

Another point that makes it easier to store and remember information from a physical book is the multi-sensorial effect. You do not only read the words inside the book with your eyes. You also touch the book with your hands, you smell it, and even when you are not reading it, you see it on the table, with the cover picture and the title printed on it. That makes for additional input; your brain connects all sensorial input to what you have been reading, rooting it more firmly in your memory than if you only read the words on a screen, i.e. your brain would deal with just the one info, not backing it up with other input.

My kindle is still the first generation. It has no back light, but uses a technology called e-ink. A layer of molecules is behind the magic - imagine those molecules as tiny balls, with one half painted white and the other black (or dark grey). When you "open" a page on your kindle, the letters you see are the black halves of the tiny balls of e-"ink", and the spaces in between the letters are the white halves showing.


simplified representation of e-ink; picture from wikipedia
Whenever you press the buttons to change "pages" on your kindle, the clever little computer chip inside tells the tiny balls to roll around (on their same position) and either show their white or their black half.

That is an extremely energy-efficient way of transmitting information to a screen, which is why the battery on a first-generation kindle lasts for a very long time before you need to recharge it.

This e-ink technology also means the reading experience for your eyes is very close to the one you get from paper. With one big difference: You can also read in bright sunlight without being blinded by the whiteness of paper. (There is plenty more about e-ink here on wikipedia.)

For me, my kindle has become indispensable. I still very much love reading printed books; they will never be entirely replaced, but my kindle is the best addition I can imagine. Nearly every day, I am on trains to and from work, and take longer train trips most weekends. I much prefer the lightweight kindle to a heavy book for those trips; also, a book can bend and get smudged so easily when you are travelling, something that does not happen with the kindle. Plus I can read on my kindle while waiting on windswept cold platforms, wearing gloves; that is very difficult with a physical book.

When I am home, I usually touch my kindle only to recharge it, and read newspapers and printed books. 

23 comments:

  1. That's really interesting - most of it new to me. I have used a Kindle and it is easy, but am still stuck with books. Mrs Britain like the Kindle so much that I bought her another one...

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    1. Now that is puzzling - what would one do with two kindles, unless one is broken and needs to be replaced?

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  2. My kindle is generation 7 and has no light of its own....I have a software called f.lux on my computer to change the light when the sun goes down....But I haven't heard about this refresh rate...I'll ask my son Andy about it. I don't have a smart phone nor tablet. The only lit things I have are desk computer and tv. Modern life is.......disturbing sometimes. But I'm enjoying it. I use my kindle a lot because of arthritis in my hands, but I love real books, too. And have far too many!

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    1. What I also like very much about my kindle is that I can change the font size - impossible with a printed book, but sometimes necessary as my eyes are getting from bad to worse.
      If you click on the word "wikipedia" in the paragraph about the refresh rate, it will take you directly to an explanation on wikipedia. But I am sure Andrew can explain it even better.

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    2. That ability to change font size is a great feature, though my kindle too often changes the size when I have done nothing to make it happen.

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    3. Luckily, my kindle never does that. It must be very inconvenient.

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  3. My Kindle is also 1st generation and I do like the similarity to the printed word. Now that I travel by plane less than I used to I've not been using the Kindle as much. In fact I'm ashamed to say that I seem to have forgotten to make time to read books much at all. Ironically having spent so much time in hospital recently I had time to read many books but could not concentrate long enough so ended up reading The Times every day and doing the general knowledge crosswords and word games.

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    1. Yes, isn't it unfair that when we are ill and would have "all the time in the world" to read, we oftn can't read much (or not at all) because we are too exhausted, have a headache or are otherwise affected?
      Some years ago when I was house-bound with a big fat cold (or a flu, I never know how to discern the two), I could not read long for lack of concentration. Instead, I re-watched my entire collection of Harry Potter films over the period of one day and one night. The next morning, I felt hungover.

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  4. Your thoughts about reading have made a miracle coming out of books clear. Moment of bliss.

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    1. I am glad my thoughts made something clear to you, crane - thank you!

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  5. I also have a first generation kindle and I like it too, but, like you, I also enjoy reading a real book more. I also have a kindle app on my iPad and this seems to have the same disadvantages as reading anything else on a computer screen. I'll investigate the refresh though, that seems to chime with what I feel myself - my eyes are simply tired after reading a screen for too long.

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    1. The iPad has of course a "normal" screen and does not work with e-ink like our dear old kindles, therefore even with a kindle app, you will only be able to show kindle contents without the whole kindle experience.

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  6. I bought a lot of books the first year that I owned a NOOK and sometimes I wish I'd invested that money in actual books, even though they're more expensive. I rarely use the NOOK device anymore (because it's large and not comfortable to hold) but instead I use the NOOK app on my phone. It's not great, reading on such a small screen, but it is really convenient.

    My husband scolds me all the time for reading on my phone right before I go to sleep, because of the blue light and some of the issues you mention, but I never have any trouble sleeping.

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    1. If you don't have trouble sleeping (with or without having read on your phone before), then there is no reason why you should not keep it up.
      Reading on my phone is getting increasingly hard for me, as my eye sight continues to deteriorate.

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  7. Well then, it seems to me that they should never have made any changes to the screen on a Kindle, they should have kept it as 1st generation! (Wonderful explanation, my friend, you really would be such a very good teacher.)
    Like you, I love books- the smell of them, the feel of them and the look of them!

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    1. Glad you liked my explanation, Kay! I must admit the e-ink explanation was originally given to me by my then colleague, many years ago, when I still worked in the field of selling point-of-sale hardware. He was very good at making me understand even the most complex technical problems.

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  8. I also meant to tell you...I was moved into a new office recently at work. The lights in there were of a bluish hue...and I was having such a time. I could NOT get anyone to understand how much this affected me. Finally, I FOUND some yellow lights in a closet and asked if it was possible if I could have them. YAY! I can now see again!
    (Please note, the long fluorescent tubes were not yellow or blue, but just tinted that way, but the difference for me was a major difference. I must be just a wee bit oversensitive to color.)

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    1. The quality (and colour) of light makes such a difference! Good job you found the kind of light you needed, and the tubes were installed in your office.

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  9. Thank you for the lesson Professor Riley. I will be sticking with real books made from paper. I like to see how far I have got and sometimes I check ahead to see how many pages are left to read in that particular chapter. Shirley received a Kindle from Frances for Christmas and is currently reading an e-book for the very first time. You have clearly given this subject a lot of careful thought.

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    1. I have indeed, YP.
      You know you can also check your progress and how much of a book you have left to read on a kindle, only that it does not tell you so in pages but in percent, at the very bottom of the "page".

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  10. I love my Kindle too - I think mine might be "second" generation (it has a touch screen) but it does still have the e-ink and grey background, and I do find that so much easier on the eyes than reading on a computer/phone screen. I also love that I can enlarge the text if needed. With some kinds of books I still find it better to read them on paper - like those that are more fact than fiction, or for some other reason you might want to go back and forth in them to check things. The problem with e-books is that you don't get the same physical sense of how far into the book a certain passage may be found, etc. But as you know, I also listen a lot to audio books - which I love, too - but in those it's even harder to go back and find the right place ;) However, I can rest my eyes while listening - and sometimes a good narrator can even enhance the experience. (That depends both on the story and who is reading!)

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    1. ... Should add that my absolute favourite combination is "whispersync" Kindle+Audible, i.e. when I have the book as both Kindle (on the Kindle) and Audible (on my phone), and (when on wifi) I can just switch from one to the other at any time, and the book syncs automatically to the right page, whether I'm listening or reading with my eyes... :)

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    2. That whispersync thing sounds great! I have not listened to any audio book since the days when I was a little girl and loved listening to our collection of cassettes (tapes). My sister and I had a whole series (Enid Blyton's The O'Sullivan Twins), which we loved and knew by heart - we could speak the dialogues along with the tape :-)

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