Ensuring ePub conversion doesn't touch images

Hi everyone:

My very first eBook ( http://www.lulu.com/shop/alexander-karasev/roundny-the-round-project/ebook/product-22104130.html ) displays photos that have a pixelated, jagged quality to them. The product page has a preview ePub that shows the same problem. In my source document, the images are 300dpi high resolution photographs, themselves carefully scaled down from 36MP originals with no artifacts.

After the Lulu ePub conversion, the images do not look good enough for a photo-oriented ePub ebook. I have perused the Lulu Complete eBook Creator Guide pdf. The images in my resulting ePub clearly have a MUCH lower quality than that described in the "High-Quality Images" section (250 KB and 2 megapixels), so I have the following questions:

1. Exactly what conditions trigger ePub image conversion? Is it total image size in megabytes, image pixel dimensions, image pixel size relative to its size on page (i.e. dpi), total ePub file size, or a combination of these thresholds?

2. What are the specific threshold values?

3. What are the steps to make sure Lulu ePub conversion does not touch the images?


Thank you!

Comments

  • Just KevinJust Kevin Lulu Genius

    They look OK to me, what there is in the Preview, and I am viewing on a PC on ADE set at zoom, not a Smartphone or other form of small device.

     

    I think what you describe is just the nature of ePubs and perhaps ePubs are not the right media for photobooks?

  • Em_PressEm_Press Professor

    Hello Alex,

     

    Make your images between 96 and 150 dpi, 6 inches maximum width and height. Preview epub in Adove Digital Editions before you submit the file to Lulu.

     A citizen of the world.

  • I used properties in the word document to make all images a maximum of 220 dpi. Now the come out sharp in ebooks, I also compressed them in Word. 

    Still trying to get them in the correct postion. They are all over the document, some even missing, some overlapping with others and I followed all the instructions.

  • Just KevinJust Kevin Lulu Genius

    Dare I suggest you pay Maggie to do it for you?

  • Em_PressEm_Press Professor

    Hi Wolf,

     

    All you need to do is select In Line with Text Wrap option. Try it; it sounds like you're on your way.

     A citizen of the world.

  • potetjppotetjp Professor

    WolfBerg a écrit :

    IStill trying to get them in the correct postion. They are all over the document, some even missing, some overlapping with others and I followed all the instructions.


    Whether your book is printed or digital, every picture has to be anchored to a character, a paragraph of a page. I can do this very easily with WordPerfect. I suppose you can do the same with MS-Word.

  • Kevin, thank you! I have since updated the preview (and the book) so it looks better.
  • Hello Maggie, and everyone:

    Thank you very much for your help! I've revised the book and updated the preview with the improved best practices, and my images aren't downsampled/re-compressed anymore.

     

    Since I didn't want to rely on a word processor (Libre Office, in my case) for image processing, I created an export preset in my Adobe Lightroom to output my Lulu ebook illustrations with the following settings:

    1. JPEG with sRGB color; all metadata removed except copyright
    2. Raster size of 2.0 megapixels (1414x1414 pixel square images and e.g. 1732x1155px for a given rectangle)
    3. File size up to 250K

    This resulted in fairly good looking images, esp considering they were computed in one shot directly from high quality originals.

     

    What still surprises me is that the dpi setting (whose intent is to control how large an image of given pixel dimensions, prints out on paper) has a bearing on ePub books. Given the diversity of screen resolutions and sizes I'd expect tagging an image to take 100% of available screen width (or height or both) vs say 30%, would make more sense. Yet, the dpi was somehow (awkwardly and inconsistently) honored by a bunch of ebook readers I've tried, so I had to settle on some value that made sure the round pix take close to full page width on most ePub readers.

    Thanks!
    Alex

  • Just KevinJust Kevin Lulu Genius

    What still surprises me is that the dpi setting (whose intent is to control how large an image of given pixel dimensions, prints out on paper) has a bearing on ePub books.

     

    It's all the same thing nowadays because almost everything viewed on a screen (to be printed out or not) is created by tiny dots called Pixels which are Dots Per Inch.

  • Of course. The difference I was referring to is, when one prepares a given print job, the page size is very scific and once an image is printed at a given size, that's the size it stays (unless we're talking about inflatable baloons and other things completely beside the point).

    In that realm, something like the following train of thought makes sense to me: "I want this 2Megapixel square image to print 5 inches wide, hence it's 236dpi. The print process is 300 dpi native, so I have a choice of either finding a slightly larger (than 1414x1414px) copy of this image, or print it 4.7 inches instead of 5 so it prints at 300dpi, or hope the printer's scaling process is good enough where 236dpi interpolated to 300dpi looks good enough."

    By comparison, this is nonsensical to me:" make this image (for digital distribution across a bunch of unknown devices) 100dpi and 5 inches." Five inches on what?? On my iPhone4? On my AppleTV? On my Dell 30" monitor? On my Sony eBook reader? All these screens have different sizes and different screen resolutions. It is absolutely true that each screen has a particular "dpi," and the software that in some cases chooses to treat those hardware pixels literally 1:1 relative to software/stylesheet rendering pixels, and sometimes not. But an eBook targets an unknown mix of these different screens.

    That's why I said I wish there were a way in ePub, whose whole point is to be as generic and reflowable as possible, to specify that an image take a given percentage of viewable space or something along those lines - sort of like what is possible in cascading stylesheets on the web.

  • Just KevinJust Kevin Lulu Genius

    The point is they may all end up read on many types of devices of all shapes and sizes, so ePubs have to allow for that. People often download them via cellphone wireless, which is not that fast, so files have to be small, not least because many of the smaller devices have small rams.

  • Thanks to all and thanks to Lulu support (Sheridan) I got it.

    After I inserted the pictures correctly, I moved them, which changed the setting. Some I could correct by just changing text wrapping from top and bottom to in line. But many I had to delete and insert again at the right location. I also had to insert a paragraph after the picture and before the caption.

     

    Sofar it all works, only problem left is the pictures have different sizes. I wish I could enlarge them all, use the same size, and format the caption to the width of the picture and right below it.

  • Thanks to all and thanks to Lulu support (Sheridan) I got it.
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