Ghost text in PDF viewer

[HelloMoz]

Many PDF have the text overprinted to the rendering:

Seems to be especially PDF from academic publications, e.g. https://pubs.acs.org/doi/epdf/10.1021/jm100020w (open access, not paywalled)

Does only happen when PDF is opened within the website, not when downloaded and PDF opened as file within FIrefox.

Cheers,

[jscher2000]

The code websites use to render PDFs as HTML and CSS is similar to the code Firefox uses, but one notable difference is that add-ons are not allowed to inject code into Firefox's built-in PDF viewer. So one possible explanation might be an add-on that modifies styles or colors on websites. There is a transparent text layer that is aligned on top of the background image to allow Find in page and selection/copy. If I use the Page Inspector to make the transparent text visible and turn off the precise placement of the text layer (attached), then I get an appearance similar to your screenshot. Can you think of any add-ons you might have installed that could be making those changes?

[HelloMoz]

I couldn't identify an add-on causing this in Troubleshoot mode, the only add-on in question could be an ad-blocker, but that didn't change anything. However, the Firefox in question is an ESR (115.14.0esr), so probably that'll be the reason. Thanks!

[Agentvirtuel · Accepted solution]

Hello

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@HelloMoz wrote:

the Firefox in question is an ESR (115.14.0esr), so probably that'll be the reason.

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That's right
https://www.youtube.com/embed/wMgEOwsH88E

For information purposes
Firefox Release Calendar
https://whattrainisitnow.com/calendar
https://www.camp-firefox.de/artikel/891-alles-wissenswerte-zu-firefox-esr-128-inklusive-unterschiede...
https://www.mozilla.org/en-US/firefox/128.0esr/releasenotes

[monikapaaro]

This issue likely stems from how the website's embedded PDF viewer renders text layers. A quick solution is to download the PDF and open it directly in your system's PDF reader or browser's standalone viewer, where the rendering works correctly. Alternatively, checking for updates to the browser or embedded PDF viewer plugin might help resolve compatibility issues.