Kobo page turn behaviour

[pentel]

When I tap on the Kobo screen to page turn, the screen background will change from "white" to "black" briefly before turning the page. This brief black "flashing" of the screen is "painful" to the eyes.

Is there a setting I can set to prevent Kobo from changing the background to black when tapping on the screen to page turn?

[GeoffR]

Originally Posted by pentel

When I tap on the Kobo screen to page turn, the screen background will change from "white" to "black" briefly before turning the page. This brief black "flashing" of the screen is "painful" to the eyes.

Is there a setting I can set to prevent Kobo from changing the background to black when tapping on the screen to page turn?

Settings > Reading Settings > Refresh the screen every: 1-6 pages.

You can set also values higher than 6 pages by editing the configuration file ./kobo/Kobo/Kobo eReader.conf and changing the value of numPartialUpdatePageTurns=

I find a refresh every 20 pages is enough on my Glo, unless the book has a lot of images or bold text in which case more frequent refreshes are better.

[pentel]

Originally Posted by GeoffR

Settings > Reading Settings > Refresh the screen every: 1-6 pages.

You can set also values higher than 6 pages by editing the configuration file ./kobo/Kobo/Kobo eReader.conf and changing the value of numPartialUpdatePageTurns=

I find a refresh every 20 pages is enough on my Glo, unless the book has a lot of images or bold text in which case more frequent refreshes are better.

Now I'm confused. First, I don't know what the Refresh screen does. My settings for this is now at 6 pages. This is the maximum value I can set for the Kobo Mini from the user interface.

I'm not sure if you know what I'm talking about (I think you do, but I want to make sure the question is understood). The video below showed the screen background turn black on each page turn. My question is if this black background can be avoided, that is the screen background remained as "white" on each page turn?

[ShellShock]

That does not look normal to me, especially if the refresh is set to every 6 pages. You seem to be getting a refresh on every page, and they are much more noticeable on your mini compared to my Aura HD. But that might be normal for a mini. Can anyone else with a mini help?

[GeoffR]

The black flash is the page refresh, it should normally occur only once every 6 pages if you have that set in the Reading Settings.

However when reading a kepub book with the current firmware, if a page has a full-screen image then a refresh always occurs, so if you have a number of pages with nothing but images then you would see it refreshing every time you turn the page.

Edit: I should add that unlike text, images are displayed in two steps: first the image is drawn in black-and-white; then the shades of grey are filled in. For images which have a very light colour palette this two-step process can also look a bit like a flash, although different to the flash of a screen refresh.

[DNSB]

Originally Posted by pentel

Now I'm confused. First, I don't know what the Refresh screen does. My settings for this is now at 6 pages. This is the maximum value I can set for the Kobo Mini from the user interface.

Can you supply a video of your Mini showing this behaviour. The supplied link to a video of the Kobo WiFi is not all that useful.

Regards,
David

[davidfor]

Originally Posted by pentel

[FONT=Verdana]

Now I'm confused. First, I don't know what the Refresh screen does. My settings for this is now at 6 pages. This is the maximum value I can set for the Kobo Mini from the user interface.

Try setting it to something else and see if it still happens. Then set it back.

And what version of the firmware are you running? And as the other David asked, a video of your Mini would be handy.

[ShellShock]

Originally Posted by DNSB

Can you supply a video of your Mini showing this behaviour. The supplied link to a video of the Kobo WiFi is not all that useful.

Regards,
David

Ah, so that video is NOT pentel's mini! Doh!

[filmo]

I think "painful to the eyes" is being just a little dramatic. Between page turns black flash (refresh) is to reduce ghosting of faint image from prior text showing on new page.

With you kobo mini turned on, touch center bottom of screen. Next touch 3 line icon at top right of screen. Next touch "settings" box in drop down menu box. Now touch "Reading Settings". Bottom 1/2 of first reading setting page is for Page Refresh Settings. Because your reader is refreshing after 1 page Touch box that says "1 Pages" than select "6 pages" from drop down menu. Your reader should now refresh only after 6 page turns.

[pentel]

Thank you ALL for your replies and comments. I do not have the resources/expertise to supply a video. However, I do understand the problem better now, which I previously don't. First, thanks to Geoff for explaining what a page refresh is. Now that I know a 6-page refresh is, with my Kobo Mini set to 6-page, I counted and can see the black flash occurring once every 6 pages.

I confused those black flashes with those that occurs outside reading a book. For example, in the Settings menu, for each option I choose, I get a black flash. When I click the arrow back button to return to Settings menu, I get a black flash. The 6-page refresh seems not to be applicable outside reading/page turning a book. Is this constant black flashing outside reading a book normal in Kobo?

[Ripplinger]

The refresh where a page turns briefly black before displaying the text is how e-ink works, so it happens on all e-ink readers to an extent. It can be more noticeable on some readers than others. I hardly notice the flash at all on my Glo, but I also have it set to happen once every 50 pages. But the brief flash is certainly less of a disturbance to reading than if you would turn a page of a physical paper book.

That video also seems to have a really pronounced black flash, as if the reader is slowed down for some reason (such as having 3000 books in the main memory that can slow down some readers, or maybe a badly formatted book will show it happening that slowly as well).

[pentel]

Originally Posted by Ripplinger

The refresh where a page turns briefly black before displaying the text is how e-ink works, so it happens on all e-ink readers to an extent. It can be more noticeable on some readers than others. I hardly notice the flash at all on my Glo, but I also have it set to happen once every 50 pages. But the brief flash is certainly less of a disturbance to reading than if you would turn a page of a physical paper book.

Thanks for the clarifications on how e-ink works. You said you set the black flash once every 50 pages in your Glo. Is that setting of 50 pages from the Kobo Settings screen or did you have to edit the configuration file ./kobo/Kobo/Kobo eReader.conf as mentioned by Geoff earlier?

[robko]

Originally Posted by pentel

The 6-page refresh seems not to be applicable outside reading/page turning a book. Is this constant black flashing outside reading a book normal in Kobo?

Correct, the 6 page does not apply outside a book. This is because in the menus there tends to be more images and other "heavier" items that are more likely to leave "ghosting" (remnants of previous text/image on the screen that the full black flash refresh removes).

[Ripplinger]

Originally Posted by pentel

Thanks for the clarifications on how e-ink works. You said you set the black flash once every 50 pages in your Glo. Is that setting of 50 pages from the Kobo Settings screen or did you have to edit the configuration file ./kobo/Kobo/Kobo eReader.conf as mentioned by Geoff earlier?

Yes, you have to manually edit the file and change the number to something higher. Some have set it to 99 and it works out well for them, it depends on how much ghosting will be noticeable for you on the Mini. For me with the Glo, I don't notice any ghosting with the light. This is how the line is added for the Glo under the Reading section, I'm assuming it will be the same for the Mini. Change the "50" to anything you want. If you notice too much ghosting, you can always change it to a lower number.

[Reading]
numPartialUpdatePageTurns=50

[pentel]

Originally Posted by robko

Correct, the 6 page does not apply outside a book. This is because in the menus there tends to be more images and other "heavier" items that are more likely to leave "ghosting" (remnants of previous text/image on the screen that the full black flash refresh removes).

Thanks for the info. I understand a e-reader better now.