Publisher opens corrupted version of B&W document

[ciscrhMk2]

I'm scanning documents using my  Brother MFC-J4340DW printer/scanner but the PDF files are corrupted when opening them in Affinity Publisher v2.5.5. I've done some troubleshooting which suggests that colour or greyscale scans are opened normally, whereas the B&W versions are corrupted. I've also established that the problematic PDF documents open without error when opened in the Edge browser or the PDF-XChange reader app on my Windows 10 PC. Unfortunately the colour & greyscale versions of the PDfs are over 2MB in size whereas the B&W version is only 142kB, which would be more than adequate for my purposes. The B&W PDF file is displayed in Publisher as a white band covering about 10% of the top of the A4 pages.

The printer may be producing corrupted versions of the B&W PDF documents, but the two PDF viewers I used in the testing both open the B&W documents without issue, so I'm inclined to think that Affinity Publisher should do so as well 🙂

I have attached three versions of the 2-page test files

scanFromPrinterTrueGrey.pdf scanFromPrinterColour.pdf scanFromPrinterB&W.pdf

[ciscrhMk2]

BTW, I'm not a new member, I've just had to create a new account because I can no longer access the old one & the account recovery mechanism won't talk to me.  I've been around since PagePlus V1 🙂

[David in Яuislip]

Ghostscript reports an error which might be the cause, however
gswin64 -sDEVICE=pdfwrite -o scanGS.pdf scanFromPrinterB&W.pdf
produces a file that Publisher V1 can read, quality looks same as input file comparing both in Chrome

scanGS.pdf

[ciscrhMk2]

Sometimes PDF-XChange reader reports errors when I open PDF files and also offers to repair them. This generates a new version of the  PDF file which loads without error. However, PDF-XChange is not reporting any errors with the files I've been processing in the last couple of days.

I can generate a new PDF version of the errant files by opening them in PDF-XChange & printing them using the Microsoft Print to PDF driver, but the new file is ridiculously large, even after I've used yet another utility to compress it.

[lacerto]

There is nothing wrong with your B/W PDF scans, it is just that Affinity apps do not support monochrome (1-bit) images at all, and threshold them incorrectly to all black  (8-bit grayscale) images. You can place the PDF in an Affinity app in the default "Passthrough" mode and then export the document to PDF at document dpi (192) to have the monochrome mode and accuracy and also compression rate retained. But you cannot open for editing or place these files "interpreted", because Affinity apps cannot interpret (understand) monochrome bitmaps. You can see this simply by switching the placement mode between "Passthrough" and "Interpret".

Attached is a PDF export from Affinity Publisher when the B&W PDF is placed as passthrough and exported at document DPI.

scanFromPrinterB&W_export_affinity_192dpi.pdf

[ciscrhMk2]

Thanks, that is useful, I'll look into it when I get some free time. There's something odd going on because I don't get what I would consider consistent results in Affinity Publisher from my various test documents. Unfortunately most of my time at the moment is being taken up with generating lots of scanned PDF files which I need in a hurry!