Tip for slow PDF view render in Zotero 6 and 7

I recently tried the Z7 Beta hoping that the new pdf.js would improve rendering speed for large color pdfs. I was quite disappointed, as the performance is essentially identical to Z6. That got me searching for a a different workaround and I stumbled across this solution.

So I recently tested some different approaches on books from Archive.org which are scanned in color and have OCR. Some are very slow to render when scrolling to a new page in Zotero 6 and 7 Beta and any browser using pdf.js. Very typical to take 20-30 seconds to render a new page when scrolling. Jumping pages by entering a page #, however, takes only 2-3 seconds.

What I discovered is that saving as a PDF/A (any version) compliant file fixes it. Instead of 20-30 seconds, pages appear and render in 2 seconds or less, and it does not matter whether the pdf is color, black and white, 30mb file size or 400mb file.

However, on the larger files, I do see that Z6 is actually faster than the latest Z7 beta 39.
  • Could you provide a link to the file that is faster on Z6 than Z7?

    Also try the latest beta to see if there is any difference.
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