Hi, I’ve created a 180 page book with a lot of 300dpi images. I chose LibreOffice because it doesn’t downsize the resolution.
Amazon’s kdp printing has a 65meg threshold for pdf’s. Mine comes in over that. Is there anything I can do while creating the pdf that might make it smaller without compromising the images’ quality? or, is there something I can do in Writer that could help.
Thank you!
OK, but what is the physical size of the images? Have you optimized them to the used size before you inserted them into the document? The resizing feature of the LibreOffice will not optimize the images the pysical (pixel/byte) size of the images remain at the original value. You must RESAMPLE the imags with an image optimizer software for the used view size (inch or mm size) located in the document.
Not while creating the pdf. If your images are linked, not embedded, you may optimize .jpg (for example Irfan-view has a mode for this). Also changing from jpg to png may give different sizes, but that would break links. It is a complicated topic, as compression depends on the depicted objects. I had a bunch of photos of antiques and all jpgs of oriental carpets were to big…
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During creation: Don’t include the .odt and if there are options avoid tagged-pdf, as this increases size.
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On the other end you may google for software wich optimizes pdf, as I don’t think LO has this as priority.
Thanks. I’m leery about optimizing because I’m concerned what it may do to picture quality. It’s a career book with lots of images of artwork, linework, as well as fully rendered images.
Having said that quite a few images are larger than they appear in the book and scaled down in the program. I didn’t think that would matter, because I thought (perhaps incorrectly) that once converted in the pdf that wouldn’t matter. I do have the pdf output checked to make resolutions 300dpi.
It would be a considerable job but I could take the photos back into PS and scale to exact print size if that would make a difference.
Thanks for your help.
Best,
Rick
I find that reducing dpi to 150 dpi gives a better result than excessive jpg compression of a 300 dpi file.
If the images are not photographs but graphs and other simple vector type objects or B&W, then reducing the number of colours while retaining dpi and saving as png can make savings in space although all the images need to be optimised beforehand in a graphics editor and then set the export to not touch the images.
The assumption is that the images are 300 dpi at print size otherwise you are including information that will not be used in the output.
Thank you. The images are scans of actual art and also photos. Reducing to 150 would seriously compromise quality.
150 dpi at nominal width of 420 mm = 300 dpi at nominal width of 210 mm, that is, both are 2480 pixels wide.
My actual point was that excessive jpg compression at 300 gives worse results than moderate or light jpg compression at 150 dpi so don’t be tempted, like so many, to increase the jpg compression until the file size is small enough.
Thanks for the additional info. yes, I did get your point about the compression on a 300dpi image.
No, I didn’t, and thank you. That’s why I asked. I know that if I took the images into PS, and reduced them to book-used size, that would shrink the size of my LibreOffice file.
But when i convert my original to a pdf, it is turning the whole thing into a picture, so would changing the sizes amount to anything in the size of the pdf document?
If I have an image that is 11x15" at 300 dpi, and I scale it in the book to six inches across, I don’t know if that keeps the 300 dpi or if I have effectively raised the dpi almost twice. However, when I make the pdf, I have checked make all images 300 dpi, so I would think that would take care of that for the pdf.
Thanks for your help, and if you can answer the above question about whether resizing would affect the size of the pdf.
Best,
Rick
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Not, the PDF export feature of the LO will not create one huge image from the content of a Writer page. The images will present individually in the PDF file, and the text part become as “labels”.
Can you upload a “small” (one or two page) ODF type sample file here?
Oh, thank you for explaining. I had a complete misunderstanding of the pdf parameters. It maakes sense now, that for editing purposes, it isn’t creating one picture object of a page(s). I will check sizes and re-scale. Thanks again!