jpg and jpeg conversion to png in editor

[rjwse@aol.com]

Is there a fast method of converting jpg and jpeg image files to png inside the editor? jpg and jpeg images produce jaggies when sent to Amazon while png do not. I have been exporting the jpeg and jpg files from the editor to a blank folder, then processing the batch with "mogrify -format png *.jpg", importing them back into the editor, then renaming them individually, then bulk deleting the jpg and jpegs. Best regards, Pop

[JSWolf]

Originally Posted by rjwse@aol.com

Is there a fast method of converting jpg and jpeg image files to png inside the editor? jpg and jpeg images produce jaggies when sent to Amazon while png do not. I have been exporting the jpeg and jpg files from the editor to a blank folder, then processing the batch with "mogrify -format png *.jpg", importing them back into the editor, then renaming them individually, then bulk deleting the jpg and jpegs. Best regards, Pop

Converting JPG to PNG won't make any difference. The PNG will be the same quality image as the JPG.

[kovidgoyal]

select all images, right click export all the files. The right click and change extension to png. Then convert the files. Then delete the files. Then import the converted files. Be careful in case the files are supposed ot be in some sub-folders. In that case do one sub folder at a time.

[rjwse@aol.com]

select all images, right click export all the files. The right click and change extension to png. Then convert the files. Then delete the files. Then import the converted files. Be careful in case the files are supposed ot be in some sub-folders. In that case do one sub folder at a time.

Thanks for this. I never would have thought this step saver of changing the suffix from jpeg or jpg to png BEFORE actually doing the image conversion. I did not know this could be done.

Converting JPG to PNG won't make any difference. The PNG will be the same quality image as the JPG.

The calibre tag editor image, the calibre viewer image, and the pdf file created by calibre all look good, but the PDF "downloadable proof" from Amazon does not like JPEG or JPG for some reason.

Thanks to all, Pop

[Quoth]

Don't use an ebook as source if you are publishing on paper. You export a PDF with Amazon desired margins defined in the wordprocessor page styles.
There is then no need at all to download from Amazon, the PDF you upload is what they use. You do need to preview on screen and check that the cover works and the page trim works. They'll tell you if the margins are violated.

A PDF download is pointless for actual ebooks. You have to do a test buy of mobi, azw3 and KFX on a suitable ereader(s). Kindle preview is also a bit pointless.

On ebooks Amazon will reprocess any large jpegs and may change PNG to 256 colour indexed GIF.

jpeg = jpg, just different text for the file ending. No effect.

Only use Calibre's PDF converter to convert ebooks for you own use. Publishing on paper doesn't involve Calibre at all (only used to make ebooks). The best way is properly style pages, header, footer etc in MS Word or LO Writer and then direct export a PDF.

You only use Calibre for publishing to make an epub from a docx (which need different settings to a paper edition), or exceptionally also making a "dual Mobi" for Smashwords so they can offer epub and Kindle versions. Only upload an epub to Amazon KDP for an ebook version, which Amazon converts to mobi, azw3 and kfx.

Amazon don't convert PDFs properly formatted for paper publishing, which is the only use for a PDF in publishing.

[rjwse@aol.com]

There is then no need at all to download from Amazon, the PDF you upload is what they use.

Actually, there is a difference. That was my point. The PDF I uploaded with JPEG/JPG images looked good, but the 'downloadable proof' has jaggies. If I converted the JPEG/JPG images to PNG, then uploaded that file, the 'downloadable proof' looks good. The printed book with JPEG/PNG will have jaggies, but the printed book with PNG will not.

Don't use an ebook as source if you are publishing on paper.

All my books are in EPUB format. I upload those to Amazon as-is. I convert the EPUB format in calibre with one click to PDF, then upload that output (almost) as-is. (I post-process the 'printer offset' margin such that the outer is half-inch; inner is one-inch. I do this because Amazon does not recognize the method of printer offset used with calibre's conversion to PDF.)

[rjwse@aol.com]

The printed book with JPEG/PNG will have jaggies, but the printed book with PNG will not.

oops! Supposed to read:"The printed book with JPEG/JPG will have jaggies, but the printed book with PNG will not. "

[Quoth]

Don't convert epub to PDF ever. Use a copy of the wordprocessor source which needs different styles for an ebook (epub) and paper (a PDF).

The PDF I uploaded with JPEG/JPG images looked good,

On what? Paper proof at 600dpi print, a 10″ eink at 221 dpi or 300 dpi, or a regular laptop or PC screen at about 96 dpi to 120 dpi, or a 4K screen at about 120 to 240 dpi?

I do this because Amazon does not recognize the method of printer offset used with calibre's conversion to PDF

Set left & right paper styles for Front matter, contents, first page of chapter, body of book, end matter etc. Then Export from Word (unless you are using older than 2007), or export from LO Writer (Better than Word 2007 or PDF plug-in for older MS Word).

The Calibre PDF output is for a tablet, or local print etc, when you ONLY have an ebook (epub, mobi, lrf, azw3 etc). Otherwise for a publishing ready PDF export direct from Wordprocessor.

If you ONLY made & edited an epub and don't have a docx or odt, then convert the epub to RTF or docx and fix styles in Word (or LO Writer saving in odt and only an extra Save As for docx to make an epub.

It's subpar to try and use the same format of file for epub and pdf.

I've done conversions to epub for 10 years and from a properly formatted Word or LO Writer exports of PDFs for over 25 years. I've uploaded PDFs to five POD outfits inc Amazon. And used local duplex laser. The whole point of PDF is you get exactly the same everywhere if its from Adobe or export from a Wordprocessor. Calibre is for reflowable ebooks, not fixed layout like PDF, though if you ONLY have the ebook and want a PDF for personal use (NOT PUBLISHIUNG) Calibre works.

[rjwse@aol.com]

Thank you for your input. I used Word and LO in the past, but gave up using word processors entirely. I put text directly into calibre's tag editor then add tags and classes. I use quite a bit of visual complexity with boxed images with side, top, and bottom captions. To be sure, I have been aware that this is considered garish and tasteless, not to mention 'busy.' To do these things I am using a lot of Flex. For some reason Amazon does not recognize the much more efficient Grid, Columns, etc. I switched to CSS entirely because the desired correct-looking output with a word processor always will alter itself during its rule-based conversion to PDF. Using CSS I can control all aspects of placement such that there is no drift. If and when Container Queries ever become implemented I suspect there will be a more visually rich landscape for ebooks and ereaders. So far, I have not seen any dedicated ereader as good as calibre itself. Best regards, Pop

[Quoth]

switched to CSS entirely because the desired correct-looking output with a word processor always will alter itself during its rule-based conversion to PDF

Not true.

Also if wordprocessor styles are used correctly they map exactly to CSS. Perhaps for final release you might edit CSS of images.

Well, no-one can help you it you insist on a back-to-front generation of PDF for paper & ebooks.