Reader with good grayscale support

[Agama]

I've recently made an ePub which has some paragraphs with a light grey background. No problems on my Sony PRS-300 but the background appeared white on a Kindle PW, (converted to azw3 with calibre and checked the result using kindlegen - see https://www.mobileread.com/forums/sho...d.php?t=202207).

I'd like a faster ePub reader than my Sony, ideally with touchscreen and good collections management, but now I have another requirement: the ability to render grey paragraph backgrounds!

(I also want to make sure that ePubs I post to MR work as intended on as many readers as possible.)

Attached is a simple test ePub with various shades of grey. (It's deliberately a 2-page document to force a white 'cleaning' page before the actual tests.)

On Sony PRS-300, ADE, calibre reader and Firefox all the 8 shades show up differently. The Sony has to mix its limited shades so some appear 'smooth' and others a bit 'grainy' but all are different.

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

On Pez (Hanlin V5) there are no stripes at all. (See above thread).

If anyone would like to test this on other readers and post their results then I would appreciaite it.

[Ripplinger]

On the Sony PRS-350, all the greyscales appear smooth and each is different, none are grainy at all. And the screenshot off the reader renders each shade exactly as you specified in #xxxxxx value. I would expect all Sony readers after this point to render the shades smoothly.

Kindlegen, Kindle Previewer, and Kindle for PC sometimes don't display exactly as it would on the reader itself, so I'd go by what others have posted here as their results on their various Kindles.

[Agama]

Thanks. Those are certainly much smoother than my PRS-300 and, as you say, a good indication of what to expect from newer Sony's as well. (T2 to the top of my list!)

[Agama]

Can anyone tell me how the Kobo Touch does with the test? This is another reader on my shortlist.

[KevinShort]

Originally Posted by Agama

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

On the Kobo Glo the result is the same.

[Ripplinger]

Not believing all newer readers wouldn't render the greys correctly, I looked at mine again with some adjustments. At the default settings, the greys appear as you said: 1 and 2 appear white; 2 to 5 are light grey and all appear to be the same; and 6 and 7 are darker than 2 to 5. I originally had my settings a bit darker, so they all appeared different on my reader. Even though when set to default where they look like only 2 shades of grey, the screenshot still turned out showing all 7 shades as I posted above. And that I really find odd.

Perhaps a better test might be to use one of the images from this post. I used the 2nd image from the first post and stuck it into the epub and tried again. This time, all 16 shades were visible on even the default or lightest settings for my reader.

Maybe it's just a case of the original greys not having enough variance between them, so they don't include the 16 shades of grey that e-ink will display, if I'm making sense how I'm trying to describe it.

[robko]

On the Kobo Glo it will show the image file correctly (same as displayed in the forum post). It's not a hardware limitation.

[Agama]

The significant difference here is that images seem to be rendered differently to paragraph background colours. With images readers seem to dither their 8 or 16 greys, which is what you would expect from image rendering with a limited palette.

However, with background-color style there seem to be different approaches. My PRS-300 dithers, hence the 'smooth'/'grainy' results, whereas other readers seem to snap to the nearest grey that is not dithered. Both methods are valid but produce different results.

I'll test more with my PRS-300 and KPW to try and find a good compromise - at least I can ensure that my grey background paragraphs don't end up white!

Thanks for all the info.

("seem" = 'educated guessing')

[John F]

Originally Posted by robko

On the Kobo Glo it will show the image file correctly (same as displayed in the forum post). It's not a hardware limitation.

Are you talking about the attachment in post 1?

I tried it on my Kobo Glo. White and Grey 1 are the same. Grey 2-5 are the same. And 6 and 7 are the same.

[robko]

Originally Posted by John F

Are you talking about the attachment in post 1?

I tried it on my Kobo Glo. White and Grey 1 are the same. Grey 2-5 are the same. And 6 and 7 are the same.

The epub attachment did as you said, the actual IMAGE (picture) in post #6 is what shows properly. I think the explanation that in post #8 says.

[John F]

Originally Posted by robko

The epub attachment did as you said, the actual IMAGE (picture) in post #6 is what shows properly. I think the explanation that in post #8 says.

Gotcha. Sorry for the confusion.