Hello to every one of you. I've solved this issue last days, doing as I said : limiting the case where ADE (and equivalent) has to downscale... Of course, there will be always case where it will be wrong on scren, but now (doing my best) I'll can say it's the Adode fault (or strategy - I'm more inclined to think it's this second reason, since they have all the background and technical in-house capacity)... Well, I'll try to react to every of your posts below.
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Originally Posted by Toxaris
If it is for the cover, you could try wrapping the image in a SVG. I am told that the quality of the resize is better then.
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I've taken a try with SVG and it's effectivelly a fabulous way (I'll keep it in mind for future projects), but not in my specific case... Because I absolutely need to keep text has being rasterized in bitmap (a matter of copyright). And image embeded in SVG in not att all vector. To have text being treated as vector, you need to write it in plan text in the SVG XML file, to do it be interpreted by the SVG rendering engine.
Quote:
Originally Posted by mzmm
i've found that image quality on ADE is notoriously poor, and agree with Jellby that this is likely due to the downscaling algorithm that ADE uses. i found a thread hidden away on an Adobe forum suggesting that best results are achieved by using 300dpi PNGs. however, i don't find that there is really a noticeable improvement in the image quality, and of course it greatly increases the size of the ebook if you have more than a few images.
here's the thread with a fairly long discussion about image quality on the Adobe forums
--edit
another way that i've found to maintain a slightly higher image quality in ADE is to set fixed image dimensions, but in most cases i find this not a useable solution because the image of course won't scale with a resize of the viewing area |
Happy to read it's the ADE fault since I've lost one week on this issue (oops)... I'll read this Adobe Form's thread for sure ; thanks for the link.
About fixed image size : yep, it's an option, but the majority of software-firmware reader downscale very well (even IE, if you directly reach the XHTML doc insite the ePub does better than ADE or Sony Reader for C)... So, I don't allow upscaling (to avoid blur), but still authorize downscale.
Talking about cover, what is very strange is that big definition is everywhere recommended (see Smashwords, Amazon, Barnes...), but - seing this ADE behavior - definitivelly not the right way when your cover contains a lot of rasterized text. In fact, it's what I did before to see this issue : my generated images were a big ones.
About the resolution (in dpi), it's a common mistake to think it has an influence on computer's screen... In reality, it has not any when pixels have fixed size. The resolution does only matter for printing (there're not any fixed pixel size on paper), faxing... All these output where the device can master the pixel size (then, the density). So, 600*800 in 96 dpi or 300 dpi are exactly the same. In PNG, the resolution (in dpi) is only an added metadata like an indication in case you have to print this image.
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Originally Posted by HarryT
Perhaps I'm just not fussy enough, but I don't see the left-hand image in the original post as "disastrous". Do you think it's bad enough to put someone off buying the book?
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Thanks a lot, it's reassuring to read this. Well, in my mind, yes, it's unacceptable... but I'm maybe a little bit perfectionist, it's not false
Quote:
Originally Posted by mzmm
more often than not, i've found that people do balk at the image quality in ADE, especially if they're also comparing it to an iPad, for example, or if they've edited the images themselves.
line art is where it's really apparent, though (see the link in my previous post)
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Quote:
Originally Posted by SBT
...especially if you render the text bit inside the SVG as either SVG-text or as SVG paths.
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Again an interesting testimonial who reassure me. Thanks to you too. On my side, I do my possible to create quality (whatever be the time I spend), but when I see I can't go deeper, it's always good to know why. So, here a message to Adobe and Sony (since we're talking about ADE, but Sony Reader for PC is bad too) : please, change your downscale algorithm ! I think it's the good time to do it
Good evening and very thanks for all your feedbacks.
PS : long post, but I don't re-read... No time. Sorry for eventual typo...