ePub to azw3 paragraph background-colour

[Agama]

In an ePub to azw3 conversion I have some paragraphs with a background colour of #f0f0f0. This renders correctly in ADE, calibre reader and on my 8-greyscale Sony PRS-300, but it does not show in the azw3 - either on an actual Kindle PW or in Kindle Previewer. I have used default conversion options for the azw3.

Tweaking the azw3 shows that the background colour has been converted, so it seems it is just not rendered. Do I have to use particular shades of grey to work with Kindles?

[kovidgoyal]

Never heard of this one, amazon's html renderers tend to have lots more bugs than epub renderers (they're newer) so this may well be one of them. Try creating a simple test html file and converting that. ALso try converting it with kindlegen to verify it isn't a conversion problem.

[Agama]

It does seem to be a rendering issue.

With background-color:#f0f0f0 calibre viewer, ADE and Firefox all display the same shade of grey but Kindle PW and Previewer show white. Dropping down to #e8e8e8 shows on all these devices, although it is a lighter shade of grey with Kindle rendering than on the others. So I can either compromise on #e8e8e8 or do some more thorough testing and see how various shades of grey vary on Kindle.

Using Kindlegen gave the same results as calibre.

(I wonder if ePub readers from different manufacturers also render colours differently.)

[Agama]

I've done a bit more testing and it definitely seems to be a rendering issue.
Attached is a simple test in ePub with various shades of grey. (It's deliberately a 2-page document to force a white 'cleaning' page before the actual tests.)

In calibre reader, ADE for PC and on my Sony PRS-300 all 8-shades show up differently, (although the dithering is quite apparent on the Sony with some of them - presumably because it only has 8 actual greys to use).

On Kindle PW the results are very different:

White and Grey 1 are both rendered as white.
Greys 2 to 5 are light grey but all the same.
Greys 6 and 7 are the same as each other but darker than 2 to 5.

If anyone feels inclined to test on their own reader and report back I would appreciate it. (I want to make sure my books render as expected on any device).

Thanks!

[theducks]

Originally Posted by Agama

I
If anyone feels inclined to test on their own reader and report back I would appreciate it. (I want to make sure my books render as expected on any device).

Thanks!

on my Pez (Hanlin V5)
No stripes show at all. (not your fault)

Looking Very Close at a angle, White is lighter and there is a distinct gradient between Grey 7 and 'the end' of the screen

So much for 8 levels

[Agama]

Originally Posted by theducks

No stripes show at all.

Interesting, and thanks for the info.

My Sony only has 8-levels but it achieves many more shades by mixing pixels of the greys that it can manage, so all 8 tests show a subtle change in level. Some end up looking very 'smooth' and others look a bit 'grainy' so maybe sometimes I've hit the non-blended greys.

Perhaps readers also differ when rendering paragraph background-colour as opposed to rendering an image. I wonder if some readers snap to the nearest non-mixed grey.

[theducks]

Originally Posted by Agama

Interesting, and thanks for the info.

My Sony only has 8-levels but it achieves many more shades by mixing pixels of the greys that it can manage, so all 8 tests show a subtle change in level. Some end up looking very 'smooth' and others look a bit 'grainy' so maybe sometimes I've hit the non-blended greys.

Perhaps readers also differ when rendering paragraph background-colour as opposed to rendering an image. I wonder if some readers snap to the nearest non-mixed grey.

I have run various firmware (Astak,L-Book,Jinke), This version is from Jinke and does not allow you to set the screen 're-flash?' mode. I have noticed other images are washing out (appear, then washout) when the text paints. Interestingly, cover images (no HTML Text), look fine.