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?

[Services]

Thanks for the detailed explanation—that actually makes a lot of sense. I hadn’t considered that an add-on might be interfering with the way the built-in PDF viewer handles the text layer. Now that you mention it, I do have a few extensions that tweak website styles and dark modes, so it’s very possible one of them is affecting how the PDF is rendered. I’ll try disabling them one by one to see if that resolves the issue.

Also, your point about the transparent text layer being precisely aligned is super helpful—I did notice that when using Page Inspector, especially when toggling positioning and visibility. It’s interesting how such small tweaks can completely change what we see.

And speaking of subtle yet powerful layers, it reminds me of how something as simple as a freedom flag shirt can also make a quiet but impactful statement—layered with meaning, identity, and purpose.

[Agentvirtuel]

Hello

https://support.mozilla.org/en-US/kb/how-do-i-create-screenshot-my-problem

Can you provide a screenshot under your Firefox 115.

Whatever!

About the subject ESR 115.x

https://groups.google.com/a/mozilla.org/g/firefox-dev
According to https://groups.google.com/a/mozilla.org/g/firefox-dev/c/bofYvrfH9vY

Eligibility for Default on Data Collection
https://wiki.mozilla.org/Data_Collection#Eligibility_for_Default_on_Data_Collection

According to https://data.firefox.com/dashboard/hardware

https://whattrainisitnow.com/release/?version=esr

[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

---

@HelloMoz wrote:

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

---

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.

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