Image quality in ADE (on PC)

[Psymon]

Why do my JPEG images look like total garbage in ADE on my PC? It's not my computer, nor my monitor -- they look fine when I'm working on them in Photoshop, and virtually the same in Sigil as I'm working on my book (all on my PC), and when I send the book over to my iPad it's still just fine, but when I look at my book in ADE on my PC it's as though I suddenly have the crappiest computer/monitor on the planet. I've been adding in a bunch of 19th century engravings to illustrate my book, and on my PC you can't even hardly make out that there's people in the pics (full-page SVG images), all you see is squiggly lines.

Here, I'll attach two images to illustrate -- "macbeth1.jpg" is the original image, and the other is a screenshot as it appears (or doesn't!) in ADE.

[Jellby]

That looks like moiré patterns due to resizing. If I remember correctly ADE has a very poor resizing algorithm, so images not shown at their native resolution will probably look blurry, pixellated or moiréd. It could also be caused/enhanced by nonstandard bit depth settings. Is the image 8bit (color or grayscale)?

[Psymon]

Originally Posted by Jellby

It could also be caused/enhanced by nonstandard bit depth settings. Is the image 8bit (color or grayscale)?

Ah, indeed it's only 8 bit (obviously it's colour -- unless you're using a B&W monitor).

Interesting... I haven't re-done my pics now to make them 16 bit, but I see I can also go with 32 bit, too. Is there a "standard" that's acceptable (if not recommended) for EPUBs?

Thanks, in advance of trying this out to see if that fixes the problem -- I'm curious now if it will! Just wondering whether to go with 16 or 32 bit.

[Psymon]

Never mind my last post! Re the 16 vs 32 bit question, if I try to go with 32 bit in Photoshop, it tells me I'm going to lose all my adjustment layers -- so never mind that.

Also, I just tried it out with that one image (for starters), changing it to 16 bit, and it still looks the same (crappy) in ADE.

EDIT/UPDATE: Well, this is weird. I was starting to get worried about all my previous books, even though I'd tested them before and didn't recall any issues, I now wanted to check them to see if the images in those were also coming out weird like that -- but they're all fine.

I couldn't figure this out, was starting to wonder if there was something corrupt in my current book -- although the coding I used for those full-page SVG images was exactly the same.

So I took this image that I used here (from Macbeth), plopped it into one of my old books, and here's a screenshot of it, side-by-side in a two-page spread with an image of a painting -- which looks just fine!

So I guess ADE has a problem with old engravings like that, where the lines are really close together, and that creates that moire pattern? Or more of an "interference pattern," if you ask me. Strange, though, as things look just fine in Photoshop, Sigil, and over on my iPad, it's only ADE that it looks like crap in. :/

[Toxaris]

Jellby is correct, the resize algorithm is worthless in ADE and has been like that at least since version 2.

[Psymon]

Originally Posted by Toxaris

Jellby is correct, the resize algorithm is worthless in ADE and has been like that at least since version 2.

So basically... just ignore it, there's nothing one can do about it? Except maybe to not use old engravings like that, of course (since it's only with those types of images that I seem to have encountered this issue, not with photos, or paintings, or old woodcuts, just those "fine-line" engravings like that) -- but I'm not going to forego those images, they work too perfectly for my book (and I have nothing else appropriate to use in their place). :/

[JSWolf]

This is only a problem with the ADE. RMDSK (used in Readers) does not have this problem.

[pdurrant]

The image you posted is not 8-bit (indexed colour) but 24-bit. That is, 8 bits each for Red, Green and Blue. You won't get any benefit from going to 16-bits per colour.

The problem is as Jellby said - moire patterns from the poor resizing algortihm. Looking at the image you posted, that doesn't look like a scan of an actual print from an engraving, but a halftone image of an engraving.

The way I'd handle it would be to apply some guassian blur to rmeove the halftoning, and then apply just a little unsharp mask, barely enough to be noticeable at 200%.

And doing that gets the image I attach, which should look pretty good, even in ADE.

[now uploaded as a jpg full size]

[Psymon]

Originally Posted by JSWolf

This is only a problem with the ADE. RMDSK (used in Readers) does not have this problem.

That's so mindboggling, that a company like Adobe -- of all companies! -- can't get their ebook reader to render images effectively (at least, not with images like this). Totally weird, in fact, that it's an Adobe product that has that issue.

Originally Posted by pdurrant

The image you posted is not 8-bit (indexed colour) but 24-bit. That is, 8 bits each for Red, Green and Blue. You won't get any benefit from going to 16-bits per colour.

Oh, I'm not too up on that "bit" stuff (although I do know Photoshop very well, otherwise), but when I go into Image -> Mode it was set at 8-bit before. Perhaps when one uses the Save-for-web feature that converts it? I don't know, but in any case changing the mode for my working PSD file to 16 bit didn't change anything with how it ends up looking in ADE (as I mentioned earlier).

The problem is as Jellby said - moire patterns from the poor resizing algortihm. Looking at the image you posted, that doesn't look like a scan of an actual print from an engraving, but a halftone image of an engraving.

Unfortunately, those images are all that I have to work with, public domain pics I got off the 'net.

The way I'd handle it would be to apply some guassian blur to rmeove the halftoning, and then apply just a little unsharp mask, barely enough to be noticeable at 200%.

And doing that gets the image I attach (in the zip file - MobileRead auto-converts pngs to jpgs!), which should look pretty good, even in ADE.

I guess that would be an alternative, but I suppose there's a couple of considerations with taking that approach...

I really wanted the "engraving" look, as the whole look-and-feel (so to speak) of my ebook is that of an early printed book -- so it would be nice if those illustrations actually looked like engravings, rather than "semi-blurry paintings or drawings." I do realize that even on my iPad, especially in two-page mode where those full-page images are even smaller, one doesn't quite see that they're engravings, but you certainly do if you click/zoom in on them, and at any rate I'd still like to keep that "engraving look" as much as possible.

And perhaps, in that regard, to some extent my query here has been moot anyway, because I was only planning on distributing my book on the iTunes Store -- and yeah, yeah, I know, there's a LOT of reasons why I should go for more options than just that, but I'm not selling this, I'm just giving it away, I don't care about "sales" but rather that things actually look/work how I'd like them to. Let's leave the iBooks trashing for another thread, thank you.

However, despite that latter, naturally it would still have been nice if I could get my book (i.e. the images in it) to look good in ADE, too -- but if the end result is that it doesn't, and it won't, well, it's "only" those engraving images, everything else in my book does look just fine (the text, and all the other "non-engraving" images).

Not to be redundant, but it's so weird, though, that Adobe can't get it right with their ebook reader! Of all companies... strange...

[JSWolf]

Most of us would be reading using an eInk Reader or a tablet/phone. So overall, this issue won't be an issue for most. Plus, there is also Calibre's viewer that can be used instead of ADE on the computer.

[Psymon]

Originally Posted by JSWolf

Most of us would be reading using an eInk Reader or a tablet/phone. So overall, this issue won't be an issue for most. Plus, there is also Calibre's viewer that can be used instead of ADE on the computer.

Re ADE, isn't that what a lot of smartphones base their software on? I thought that was why it was important to test all our books out in ADE and make sure they look good/work well in that, because that's the case.

Maybe I'm wrong -- I thought I got that from these forums here ages ago (and is why I always test my books out in that).

[pdurrant]

Originally Posted by Psymon

I really wanted the "engraving" look, as the whole look-and-feel (so to speak) of my ebook is that of an early printed book -- so it would be nice if those illustrations actually looked like engravings, rather than "semi-blurry paintings or drawings."

Fair enough! And looking closer at the original you posted, I think I was wrong about it being a half-tone. Just very fine engravings.

In which case, I'd suggest converting to greyscale, since the original clearly isn't in colour. Perhaps something like this.

[Psymon]

Originally Posted by pdurrant

In which case, I'd suggest converting to greyscale, since the original clearly isn't in colour. Perhaps something like this.

Actually, the colour that I went with isn't the original -- all the images that I started with are various shades of "brownscale," i.e. all old paper/card stock, which I converted first to grayscale and then gave this greenish tint to (all of them the same), which colour-coordinates with the reddish hues of my heading texts. It looks nice -- if I do say so myself. I could post a screenshot of that off my iPad, if you like (just haven't bothered to do so). I'm really liking how this book of mine is taking shape, actually -- that ADE/image issue notwithstanding of course.

[pdurrant]

Originally Posted by Psymon

Actually, the colour that I went with isn't the original -- all the images that I started with are various shades of "brownscale," i.e. all old paper/card stock, which I converted first to grayscale and then gave this greenish tint to (all of them the same), which colour-coordinates with the reddish hues of my heading texts. It looks nice -- if I do say so myself. I could post a screenshot of that off my iPad, if you like (just haven't bothered to do so). I'm really liking how this book of mine is taking shape, actually -- that ADE/image issue notwithstanding of course.

Ah - I didn't realise it was a deliberate colour-cast.

Bear in mind that E-Ink ebook readers are nearly all still greyscale.

[Psymon]

Originally Posted by pdurrant

Bear in mind that E-Ink ebook readers are nearly all still greyscale.

Well, then it doesn't matter if my pics are greenish. In any case, though, as I said earlier I was only planning on putting this on the iBooks Store, so I guess there shouldn't be any issues with "colour TV."