Glo Very light pictures on ebooks

[herbert71]

Hi all,

I am really glad I found this forum, I have just bought a new Kobo Glo and generally I am quite pleased about it, however I have a major problem;

• I am wanting to read a lot of technical books, but these have a lot of diagrams and pictures, I can amend the sharpness/density of the text perfectly, but nothing changes the very very light barely readable pictures. I have spoken to Kobo Support (hmmm) they say its not possible, which kind of makes the device useless for this type of publication.

I do notice that when the page initially renders the images are very bold and dense (how I want them to be), but only for a split second before they return to very faint.

Is there a way to change this please or am I stuck?

Also what is the best format for the Glo? I have noticed that some formats are quicker to respond on the device than others - sometimes its very quick to respond, sometimes very slow.

Thanks in advance of any replies

Kind regards,

H

[BookBunny]

If you're using epubs you could unzip them and run the images through some image editing program to adjust the levels.

[herbert71]

Thanks for the reply BookBunny, is that easy to do, do I make the images darker, change resolution etc?

Is there a tutorial anywhere? I have tried looking but its a minefield for a noob like myself.

Kind regards,

H

[Urdu]

Originally Posted by BookBunny

If you're using epubs you could unzip them and run the images through some image editing program to adjust the levels.

I've tried that some time ago but nothing changed. No matter how dark the image the Glo shows an image in an epub in one way only: light, very light compared to the original image.

[JSWolf]

Any chance you could post a screen shot so we can see what you are seeing?

[herbert71]

Apologies, these are not great photos, primarily because of the flash on my camera and poor quality camera, but you can see the issue. If anything the diagram looks better through the camera than at normal eye level....although you cannot tell due to the photo, text is superbly crisp and dark/dense.

It seems a shame that it cannot apparently display diagrams/pictures properly, Kobo support suggested I buy a tablet (which i already have but obviously it does my eyes in, hence buying the Glo). I am sure I have seen examples of images/diagrams being displayed bold and crisp elsewhere on the net or is this normal "e-ink ereader" behaviour?

Thanks,

H

[GeoffR]

Originally Posted by herbert71

I am sure I have seen examples of images/diagrams being displayed bold and crisp elsewhere on the net or is this normal "e-ink ereader" behaviour?

99% of pictures display fine on my Glo, but there is the occasional one that is very light. I thought it was to do with the colour palette used for the image, but maybe it is something else. Of 400+ cover images this is the only one I have that displays too light: http://www.jackvance.com/ebooks/shop...view&q22_id=38

[herbert71]

I'm mystified then, because it's all diagrams from any technical book. As i say if anything the screenshots make it look better. Any settings on the device or calibre that i should be using?

[Urdu]

Originally Posted by GeoffR

99% of pictures display fine on my Glo, but there is the occasional one that is very light. I thought it was to do with the colour palette used for the image, but maybe it is something else. Of 400+ cover images this is the only one I have that displays too light: http://www.jackvance.com/ebooks/shop...view&q22_id=38

All covers, color and b&w, display perfectly on my Glo! The non-photographic images in any epub display vague and light. Photos, color and b&w, in any epub display fine but graphics, diagrams etc are hardly readable.

[herbert71]

@Urdu,

Exactly my friend, exactly!

[BookBunny]

Originally Posted by Urdu

I've tried that some time ago but nothing changed. No matter how dark the image the Glo shows an image in an epub in one way only: light, very light compared to the original image.

Works for me™.

@herbert71: Well it is easy, but in this case I had .jpeg files, and the program I use writes only jpg files. They're technically the same thing, but if the html files refer to a jpeg, they won't find the jpg. So if you have jpegs you either have to find another program, a batch file renamer, do it manually or replace all jpeg references in the html files with jpg..

Anyway, here's what I did:

- rename the .epub to .zip,
- open it in explorer,
- copy the image folder to the desktop.

Download this: http://portableapps.com/apps/graphic...nview_portable

Extract, run, hit "b" to open the batch window. Navigate to the image folder and add the files (right side of the batch window). Now select "batch conversion" on the left, output format JPG, check advanced options and change the output directory.

Then click on the "advanced" button. Check "convert to greyscale" and "gamma correction" (0.35 seems a good value, but might require tweaking). Then OK, and start batch.

Now copy the created images back into the zip file (overwrite images) and rename it back to .epub.

You can of course try the other image options too if you want, this probably isn't the optimal way. Also make a backup of the original epub file first!

[herbert71]

@bookbunny,

That looks brilliant, i will give it a go and report back, but your examples are perfect! you are a star! let's hope i can achieve results as good as yours. Thank you so much.

[ShellShock]

I have noticed this problem (images too faint) too. For example, family trees, maps etc are rendered far too faint. Mostly I can't be bothered to do anything about it, because even if you sort out the greyscale problem it is not generally worth it - most diagrams are too low resolution or too small to be that readable on an 6" eink screen.

[herbert71]

@Bookbunny,

It worked, although maybe not quite as good as your example, maybe the gamma as you said needs a bit of tweaking, but it is far more readable/bold than before. You are a star, I have tried to give you some more karma points, but as I already had, it wont let me!

But Thank you once again!

Kind regards,

H