Obtaining transparent PDF backgrounds

[Comfy.n]

Hi all!

By running Prince PDF plugin, today I was able to get a transparent background on a PDF converted doc, after adding this line in CSS:

PHP Code:

body  {background:transparent !important;} 


This was a really cool find I wish I'd known about before.

However, in Calibre versions post-v3.48, I can't seem to find a workaround to get non-white background below text, upon converting from EPUB, MOBI etc., unless I edit the docs/ebooks internal CSS, to set a custom background color - inserting just that line I mentioned doesn't seem to work.

Is there perhaps some Extra CSS styling I can enter in the Look and Feel section of Calibre conversion, to get a fully transparent background?

So far, i've tried:

PHP Code:

* {background-color: transparent !important;}
* {background-color: inherit !important;}
* {background-color: initial !important;}
* {background-color: revert !important;}
* {background-color: revert-layer !important;}
* {background-color: unset !important;} 


Maybe there's some general HTML element in EPUB styling I'm not aware of, to which the wildcard doesn't apply...?

Reason I prefer transparent PDF in converted documents is that it's possible to add a custom background color using tools like PDF Xchange Editor, in order to reduce eye strain.

In the attachments you may see the difference between a Prince converted doc - with the "body bg transparent" CSS line addition, and the other one converted using Calibre native conversion, which has the advantage of running batch jobs...

[kovidgoyal]

IIRC There is a prince pdf calibre plugin with which you can run batch conversion in calibre.

[Comfy.n]

Originally Posted by kovidgoyal

IIRC There is a prince pdf calibre plugin with which you can run batch conversion in calibre.

Well, I couldn't find a batch option in Prince plugin :\
Anyway, Prince is awesome, but it's easier to adjust margins, paper size, font-sizes etc. in Calibre Conversion UI

[BetterRed]

Originally Posted by Comfy.n

Well, I couldn't find a batch option in Prince plugin :\

It's a GUI PI, try selecting multiple books.

BR

[Comfy.n]

Originally Posted by BetterRed

It's a GUI PI, try selecting multiple books.

BR

I did that, it returns a message "Many books selected", "Select a single book". Additionally, I found that it doesn't like titles with slashes and maybe other special characters... Anyway, I was hoping someone would tell me something like "Hey, just add epub@page-body-* {background:transparent !god-mode-override;} to Extra CSS and you'll get it"

edit: I think what Prince PI actually doesn't like has something to do with long titles