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blurry.JPG (122,456 bytes) |
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>> When I set it to "none" it is 8,29 mb ("none" should not touch the input jpg!) None means "No compression", so yes the input jpg will be touched as jpg data is compressed and you have instructed Scribus to uncompress the data. |
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>> Additionally, maybe this should be a second issue, I noticed the image is very blurry in the editor, but looks fine in the output PDF. This is expected : to save on memory, the editor usually loads images at a reduced resolution. The full resolution is only used on export. |
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>> When I choose export as pdf with image compression set to automatic the pdf file size is 7,26 mb. Your image uses a progressive jpeg encoding which is not safe to use in PDF. When this is the case, the Automatic mode has to re-encode the image and prefers to uses lossless compression in order to avoid loss of quality. |
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Thank you for the reasonable explanation. I am trying to find a source on the bit "progressive jpeg encoding which is not safe to use in PDF". Can you reference me some specification? On the side track: I am surprised the resolution is not a little higher in the editor - to a point where images are not obviously blurry. |
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This is a case of specifications vs reality. While the PDF specifications allows the progressive jpeg encoding, a number of RIPs do not support that encoding. The cases where a jpeg file cannot be embedded as is in PDFs for safety reasons are in fact not limited to that one. I give a more extended list in issue 0016150, for eg: - JPEG file use progressive encoding - JPEG exif data uses non default rotation (eg: images using portrait orientation taken with digital cameras) - JPEG file uses CMYK colorspace: would force to use a PDF feature which is regularly misinterpreted by RIPs |
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I see. So it is about maximizing compatibility for those who do not consider all factors in PDFs. I consider this ticket as a duplicate of https://bugs.scribus.net/view.php?id=16150 |
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Yes, it is. Hence closing this issue as a duplicate. |
- Anonymous
