Can't open California Digital Library pdfs on older Kindle

MarjaE · 08-27-2017, 09:59 PM

I've downloaded a number of pdfs from the Internet Archive, and can read them on my computer.

I can read some on the Kindle, or and can process some others on my computer and then read them on my Kindle. My current technique is to deliberately bloat and then re-compress the pdf.

I can't read any of the ones from the California Digital Library section of the Archive on my Kindle. I get a note about how "some elements on this page could not be displayed," and a blank page, for every page. I may have screwed up the processing.

Does anyone know if they use a different pdf formatting approach than other parts of the Internet Archive?

willus · 08-31-2017, 12:16 AM

I just chose a couple random books. The Alice in Wonderland PDF (from the California Digital Library) uses JPX encoding with RGB images at 8 bits per color.

On the other hand, the Western Philosophy PDF (from the Universal Library) uses JBIG2 encoding with monochrome (1 bit per pixel).

You can check encoding with k2pdfopt's "info" feature (-i command-line option).

That's probably the difference between the kindle being able to display the pages. It may be running out of memory on the JPX decode, or it may simply not know how to decode JPX.

You might want to look at this post.

MarjaE · 09-02-2017, 01:42 PM

Thanks.

It's an easier way to expand the pdf, and remove incompatible security, fix incompatible images, etc.

It's not so good for compressing the pdf. 150 dpi sometimes yields jagged lettering, and 72 dpi consistently yields jagged lettering.

On the Mac 300 dpi in k2pdfopt and 72 dpi in a quartz filter usually does all right.

dwig · 09-02-2017, 01:54 PM

I've encountered IA PDFs that had the same display problems on my K3. My reprocessing trick was to open the PDF on my PC in a viewer that would successfully display the PDF and then print it to disk using a PDF virtual printer (e.g. PrimoPDF, Bullzip, ...). The resulting PDF was completely rasterized, but would display fine on my K3.

willus · 09-04-2017, 08:00 PM

Quote:

Originally Posted by dwig

I've encountered IA PDFs that had the same display problems on my K3. My reprocessing trick was to open the PDF on my PC in a viewer that would successfully display the PDF and then print it to disk using a PDF virtual printer (e.g. PrimoPDF, Bullzip, ...). The resulting PDF was completely rasterized, but would display fine on my K3.

Interesting idea. I tried this in Windows 10 with Microsoft's "Print to PDF" driver, and the drawback is that it loses the OCR text layer.

willus · 09-04-2017, 08:01 PM

Quote:

Originally Posted by MarjaE

Thanks.

It's an easier way to expand the pdf, and remove incompatible security, fix incompatible images, etc.

It's not so good for compressing the pdf. 150 dpi sometimes yields jagged lettering, and 72 dpi consistently yields jagged lettering.

On the Mac 300 dpi in k2pdfopt and 72 dpi in a quartz filter usually does all right.

What is "72 dpi in a quartz filter"?

MarjaE · 09-05-2017, 08:43 PM

MacOS uses Quartz to render images, and to create pdfs.

Preview has a number of filters for graphic effects and one overly-aggressive filter for compression. Some pdf tools include a range of filters for compression, at 300 dpi, 150 dpi, 72 dpi, etc.

Older versions of Quartz sometimes removed the text layers. Newer ones tend not to.

willus · 09-06-2017, 08:38 AM

Quote:

Originally Posted by MarjaE

MacOS uses Quartz to render images, and to create pdfs.

Preview has a number of filters for graphic effects and one overly-aggressive filter for compression. Some pdf tools include a range of filters for compression, at 300 dpi, 150 dpi, 72 dpi, etc.

Older versions of Quartz sometimes removed the text layers. Newer ones tend not to.

I'm not overly familiar with OSX. How do you (1) create a PDF in OSX, and (2) change the quartz settings?

MarjaE · 09-08-2017, 12:25 AM

From a practical standpoint, 300 dpi in k2pdfop and 72 dpi in Quartz usually looks alright on my Mac, but not on the Kindle. I'm going to have to re-evaluate how I handle pdfs, so I can export readable versions to the Kindle without taking excessive space on the Mac.

Willus:

(1) Most applications allow users to export to pdf, or to print, where the print menu allows another chance to export to pdf.

(2-A) If you open a pdf in Preview, it allows users to export (not export to pdf), and pick pdf and pick a Quartz filter from the menu there. The existing Reduce File Size filter is unduly aggressive but there are instructions, somewhere, on how to create new filters.

(2-B) If you use Automator, one of its tools allows users to apply a Quartz filter to a selected pdf.

(2-C) If you use compression apps, these allow users to apply a Quartz filter to a selected pdf. These usually come with their own Quartz filters. PDFToolkit+ has lossless, 300 dpi, 150 dpi, 72 dpi, and minimal filters, among other tools.

MarjaE · 10-22-2017, 04:07 PM

Are there any tools to determine if a pdf will be Kindle-compatible as-is, or if it will require processing?

Some barriers I've encountered: (1) passwords-- even passwords to edit make them impossible to read on the Kindle without processing (2) jpeg 2000 (3) un-embedded fonts-- these get replaced with other fonts, which may be unreadable or may be mixed into jagged unreadable combinations.

08-27-2017, 09:59 PM	#1
MarjaE Guru Posts: 936 Karma: 53902736 Join Date: Jun 2015 Device: multiple	Can't open California Digital Library pdfs on older Kindle I've downloaded a number of pdfs from the Internet Archive, and can read them on my computer. I can read some on the Kindle, or and can process some others on my computer and then read them on my Kindle. My current technique is to deliberately bloat and then re-compress the pdf. I can't read any of the ones from the California Digital Library section of the Archive on my Kindle. I get a note about how "some elements on this page could not be displayed," and a blank page, for every page. I may have screwed up the processing. Does anyone know if they use a different pdf formatting approach than other parts of the Internet Archive?

08-31-2017, 12:16 AM	#2
willus Fuzzball, the purple cat Posts: 1,298 Karma: 11087488 Join Date: Jun 2011 Location: California Device: iPad	I just chose a couple random books. The Alice in Wonderland PDF (from the California Digital Library) uses JPX encoding with RGB images at 8 bits per color. On the other hand, the Western Philosophy PDF (from the Universal Library) uses JBIG2 encoding with monochrome (1 bit per pixel). You can check encoding with k2pdfopt's "info" feature (-i command-line option). That's probably the difference between the kindle being able to display the pages. It may be running out of memory on the JPX decode, or it may simply not know how to decode JPX. You might want to look at this post. Last edited by willus; 08-31-2017 at 07:49 AM. Reason: Changed "8 bits per pixel" to "8 bits per color"

09-08-2017, 12:25 AM	#9
MarjaE Guru Posts: 936 Karma: 53902736 Join Date: Jun 2015 Device: multiple	From a practical standpoint, 300 dpi in k2pdfop and 72 dpi in Quartz usually looks alright on my Mac, but not on the Kindle. I'm going to have to re-evaluate how I handle pdfs, so I can export readable versions to the Kindle without taking excessive space on the Mac. Willus: (1) Most applications allow users to export to pdf, or to print, where the print menu allows another chance to export to pdf. (2-A) If you open a pdf in Preview, it allows users to export (not export to pdf), and pick pdf and pick a Quartz filter from the menu there. The existing Reduce File Size filter is unduly aggressive but there are instructions, somewhere, on how to create new filters. (2-B) If you use Automator, one of its tools allows users to apply a Quartz filter to a selected pdf. (2-C) If you use compression apps, these allow users to apply a Quartz filter to a selected pdf. These usually come with their own Quartz filters. PDFToolkit+ has lossless, 300 dpi, 150 dpi, 72 dpi, and minimal filters, among other tools. Last edited by MarjaE; 09-08-2017 at 12:29 AM.

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09-02-2017, 01:42 PM	#3
MarjaE Guru Posts: 936 Karma: 53902736 Join Date: Jun 2015 Device: multiple	Thanks. It's an easier way to expand the pdf, and remove incompatible security, fix incompatible images, etc. It's not so good for compressing the pdf. 150 dpi sometimes yields jagged lettering, and 72 dpi consistently yields jagged lettering. On the Mac 300 dpi in k2pdfopt and 72 dpi in a quartz filter usually does all right.

09-02-2017, 01:54 PM	#4
dwig Wizard Posts: 1,613 Karma: 6718541 Join Date: Dec 2004 Location: Paradise (Key West, FL) Device: Current:Surface Go & Kindle 3 - Retired: DellV8p, Clie UX50, ...	I've encountered IA PDFs that had the same display problems on my K3. My reprocessing trick was to open the PDF on my PC in a viewer that would successfully display the PDF and then print it to disk using a PDF virtual printer (e.g. PrimoPDF, Bullzip, ...). The resulting PDF was completely rasterized, but would display fine on my K3.

09-05-2017, 08:43 PM	#7
MarjaE Guru Posts: 936 Karma: 53902736 Join Date: Jun 2015 Device: multiple	MacOS uses Quartz to render images, and to create pdfs. Preview has a number of filters for graphic effects and one overly-aggressive filter for compression. Some pdf tools include a range of filters for compression, at 300 dpi, 150 dpi, 72 dpi, etc. Older versions of Quartz sometimes removed the text layers. Newer ones tend not to.

10-22-2017, 04:07 PM	#10
MarjaE Guru Posts: 936 Karma: 53902736 Join Date: Jun 2015 Device: multiple	Are there any tools to determine if a pdf will be Kindle-compatible as-is, or if it will require processing? Some barriers I've encountered: (1) passwords-- even passwords to edit make them impossible to read on the Kindle without processing (2) jpeg 2000 (3) un-embedded fonts-- these get replaced with other fonts, which may be unreadable or may be mixed into jagged unreadable combinations.

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