19 votes

PDF signature added in Linux seen as invalid in Windows, yet certificate chain is all there

The exact message says that the validity is unknown, not that the signature is invalid. This is technically correct, given that the signature algorithm you used (SHA-1) is known broken, which means ...
Austin Hemmelgarn's user avatar
12 votes
Accepted

Is it possible to recover files on NTFS after writing to the same directory?

In particular, I'm wondering the following: if I delete files and write new files on Desktop, does that automatically mean that the previous files will be overwritten by the new files? In other words, ...
u1686_grawity's user avatar
9 votes
Accepted

Is it possible to convert Word to PDF without screenshot quality loss?

The issue is that images will be downsampled in pdf files, usually to 300dpi. But you can change that In Word, go to 'Print..' select Adobe pdf as your printer open printer properties from the "...
1NN's user avatar
  • 7,429
8 votes

Is it possible to recover files on NTFS after writing to the same directory?

An SSD works very different than an HDD, since it does some somewhat contradictory operations : Wear leveling attempts to write data in empty blocks, since this reduces the number of operations on ...
harrymc's user avatar
  • 479k
6 votes

Is it possible to convert Word to PDF without screenshot quality loss?

To get the best PDF quality, copy the text on the screen and paste into the Word document; that is, do not depend on the screen shot (variable document quality). Done as suggested, following ...
John's user avatar
  • 49.7k
6 votes

Is it possible to convert Word to PDF without screenshot quality loss?

In regards to the image resolution, I have a few things to note, and all of them are explained in more detail in a video. If you really want to use a screenshot, keep the following things in mind Try ...
Loeli's user avatar
  • 806
6 votes
Accepted

How to split a long single page PDF in multiple pages?

The best way I found to do that is to Print to PDF and use Adobe Acrobat Reader's Poster printing options. Open file in Adobe Acrobat Reader Choose Print from the menu (or Control+P) For the Printer ...
Yisroel Tech's user avatar
  • 10.8k
5 votes

Is the pdftotext command line tool for mac?

Update as of July 2023. I've found that the command brew cask install pdftotext doesn't work anymore. However, installing poppler still works and provides the pdftotext functionality. To install ...
frankyxhl's user avatar
5 votes

Is converting images to pdf lossy?

PDF is a container format, not an image format. Thus it should be possible to embed an image into a PDF, and then subsequently extract it, without recompression. However, ImageMagick convert does ...
Amadan's user avatar
  • 1,867
5 votes
Accepted

How to fix/repair a corrupted PDF?

I have been boy and man handling computer data for 59 1/2 years and for the past 40 resolving lost data problems at various levels from dodgy switches and relays, torn paper tape and moth eaten cards,...
K J's user avatar
  • 616
4 votes

Is there a command-line method to split a multi-page PDF file into single pages?

In ubuntu you'll need to install pdftk: sudo apt update; sudo apt install pdftk Then to have your problem solved, just: pdftk input.pdf burst
tonispa's user avatar
  • 41
4 votes

Extracting text from PDF?

It may be because the program that wrote the PDF has "flattened" the "ti" ligature into a graphics line-draw/fill object. It might be that the "ti" ligature encoding is ...
RedGrittyBrick's user avatar
3 votes

Is it possible to find the source of a downloaded pdf file from examining the pdf itself?

If you downloaded to an NTFS drive, the source may be recorded in an alternate data stream called 'Zone:Identifier'. An easy way to find and view alternate data streams is Nirsoft's ...
Joep van Steen's user avatar
3 votes

How to remove security from a PDF file?

you can use PDF CPU: pdfcpu decrypt in.pdf out.pdf https://pdfcpu.io/encrypt/decryptPDF note that it actually resulted in a smaller resulting file for me, versus QPDF: original QPDF PDF CPU 5,406 ...
user22859957's user avatar
3 votes

change language for pdf export in libreoffice calc

Turns out there was already an answer out there from 2013 which lead me on the right path but the solution was slightly different with my Libreoffice 7.0.4.2 : How to get page number in LibreOffice ...
cardamom's user avatar
  • 175
3 votes

How to split a long single page PDF in multiple pages?

The PDF function you require is usually termed splitting into "Poster" tiles. It can often be done in Acrobat Printing. See the answer by yisroel-tech. But it is best to check the settings ...
K J's user avatar
  • 616
2 votes

How to distill / rasterize a PDF in Linux

Solution The following code rasterizes a.pdf → c.pdf at 1200 DPI, by initially rasterize at 2400 DPI then downscale by 2 before output. Documentation. gs -dNOPAUSE -dBATCH -sDEVICE=pdfimage24 -r2400 -...
user202729's user avatar
2 votes

Error in converting a PDF to a PNG in ImageMagick

I'm using ImageMagick 7.1.1-8 and just had the same issue: $ magick example.pdf output.png magick: profile 'icc': 'RGB ': RGB color space not permitted on grayscale PNG `output.png' @ warning/png.c/...
finefoot's user avatar
  • 179
2 votes

Converting png to pdf with imagemagick: how to set the resolution?

When converting from image to pdf, lowering the density improves the resolution. convert -units PixelsPerInch -density 72 foo.png bar.pdf On the other hand, when converting from pdf to print quality ...
Sunil Shetye's user avatar
2 votes

How to keep the Highlighter tool selected in Skim?

You can select highlight as your main tool: You can click and hold the rightmost tool to have "highlight" as one of the default tools. This lets you highlight by default, and you shouldn't ...
Plooftech's user avatar
2 votes

make background white in scanned pdf?

Consider pdfsandwich which is a convenient wrapper that can call unpaper on all of the pages (and ocr at the same time.) e.g., pdfsandwich --layout single inputfile.pdf will trim black borders, ...
Joshua Goldberg's user avatar
2 votes

Convert adobe acrobat PDF to normal PDF

The official answer is ask the Author of that document to publish as a PDF/A compatible document (that will enforce it to be) a Universally Acceptable Accessible PDF Archive format attempt to ...
K J's user avatar
  • 616
2 votes

Is there a macOS command line tool for converting eps or ps files to pdf?

Probably the easiest way to get the ps2pdf utility back in Sonoma and forward is by installing ghostscript via Homebrew brew install ghostscript Here's an example (create a PDF of the ls manpage) man ...
luckman212's user avatar
2 votes

Can multiple signed PDF files be merged into one?

When you sign a PDF with existing signatures, you are also signing those signatures as part of the document contents. Copying the signatures to another document will indeed invalidate them. This is to ...
Cpt.Whale's user avatar
  • 7,661
2 votes
Accepted

Why does the keyword metadata not display in Acrobat Reader, but does in other readers?

If we ask cpdf to show the info, you can see both the old-fashioned metadata, and the new-style XMP metadata. $ cpdf synthèse_etude_canaux_communication.pdf -info Title: Etude les canaux de ...
johnwhitington's user avatar
2 votes

Is converting images to pdf lossy?

Answers at end Background For a simple "Standard" jpeg PDF In/Out is untouched, that is the input will be binary copy of output, HOWEVER that only can apply to stock PDF and an extractor ...
K J's user avatar
  • 616
2 votes

How to count pages in multiple PDF files in Windows 10?

Beautiful Excel and VBA solution here: https://www.extendoffice.com/documents/excel/5330-excel-vba-pdf-page-count.html Open a worksheet where you want to get the Pdf files and page numbers. Hold down ...
PR1's user avatar
  • 31
2 votes
Accepted

Merge 4 pdf's on one page while preserving size and adding trim marks

Ok I posted a link to a PDF you can use for the trim marks, but because the exact values you want are unknown until proven I have only done the last (top trim line because you can edit the PDF as text)...
K J's user avatar
  • 616
2 votes

How do I invert the colors of my pdf on mac?

You can do this natively, with one wisely-chosen key command - but you lose the vector fonts, you get raster png & you get one file per page. Set up an Automator action - I used a Quick Action [...
Tetsujin's user avatar
  • 49.5k
2 votes

macOS Chrome unable to save PDF via print dialog

Not a fix, but I found a simple workaround. On that Chrome print dialog, expand More settings section and click on Open PDF in Preview option at the bottom (just above that blue Save button) Once ...
y2k-shubham's user avatar

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