Compress PDF to PDF

[LaTrouille]

Hello,

I have several hundreds of .pdf scanned by an another person who have not enought compressed the files.
Now I want to.
So I had installed ghostscript and all add-on for using pdf with irfan.

File -> Batch conversion/Rename -> output format = pdf ; options = save all pages from original image -> use advenced options : Apply changes to all pages...

It's work :

Processing file: C:\Documents and Settings\ctrouillard\Bureau\TEST\0.PDF
... Ok - C:\Documents and Settings\ctrouillard\Bureau\0.PDF

1 Files - Errors: 0, Warnings: 0

But only for one page !

How can I have a batch of all pages ?

[Mij]

I have never done a batch conversion of multipage PDF myself, but since nobody else has replied my general advice for all batch conversions is to do one manually first to make sure that you have all options set up correctly.
There is certainly a Save all pages option in the PDF Save dialog and there may be options in the Open dialog that need to be correctly set too. When you are able to do the operation manually for a single file, then try the batch conversion again. Do not assume that "Apply changes to all pages" in the Advanced batch dialog will set everything for you.

[impdf]

This should work only for
Multipage PDF => Multipage TIFF => Multipage PDF

[Mij]

I had heard that,impdf, but we seem to have established that the OP in another thread currently running is doing direct pdf to pdf conversions of multipage images. His complaint is that when he runs simultaneous multiple instances of Irfanview the pages get mixed up.

[impdf]

Mij, I missed this thread.

But I guess this is difficult and quite time intensive to test. So I do not know if we could help there.

For sure I would say it is not an ImPDF problem it is Irfanview itself ;-)
No seriously, we do not have an idea but will do some simple sanity checks for the next release.

[mayavi]

yes that was my bug report.
Multipage PDF / TIFF are working very good. even the compression is good. ( for a freeware, dont compare with a commercial one)
i have converted millions, and everything works fine.
just one day i was working on a quad machine, i saw that cpu utilization was less tha 20%, so i decided to run a second instance,and it also got converted, then i tried a third instance. everything was fine. the conversions were the same, and i was happy.
but after 15 days some was doing the QC of the pics, he noticed that about 8 to 10 pics (out of 100 batch) got mixed up.
so now i am running a single thread only.
and waiting for some expert to find a solution/reason for multiple instances.
(you may or may not get this if you run a batch of small number, but you will surely find this if you run a batch of 100 or more multipage docs)

[LaTrouille]

Hello,

I followed Mij advice and do a manual and single convert PDF to PDF.
There are two ways to do that :
1) File -> Save as -> Type -> PDF - Portable Document Format
2) Options -> Multipage images -> Create Multipage PDF -> Add images (1 pdf of 3Mo and 16 pages)
It's works I obtain 1 pdf with 16 pages and 1,25Mo.
(Note that if I select "Not needed (select setting now)" in "PDF settings" Window in 1) solution I haven't "Save PDF" configuration window in the 2) solution.)

So I retry batch convertion solution :
File -> Batch conversion/Rename -> output format = pdf ; options = save all pages from original image and this time not select use advenced options.
Oh miracle, it's work also.

So I try with "use advenced options" this time and select only "rotate left" :
It's work but only the first page is rotate, the others are only compress with the add-on configuration.
And the "Apply changes to all pages" don't change anything...

My problem is so persistant, because compress is not enought for me, I want change DPI and put in Black and white.

Merci d'avance

[pvdwalt]

Hi there - I also tried using Irfanview hoping to assist in making my PDFs smaller without loosing OCR- but the compression I got is minimal and lost OCR text. I have found a tool called PDFShrink that not only shrinks the files (multiple pages at a time and batch conversions) and keeps the original OCR! So far I have been able to get a 40-50Mb PDF down to under 10Mb just using the default settings in PDFShrink.

https://usd.swreg.org/soft_shop/31652/shopscr76.shtml

Kind regards
Pieter

[Bhikkhu Pesala]

The program compresses all pictures in the pdf file with the JPEG2000 (color pictures) or the JBIG2 (b/w pictures) compression

Compressing images with propitiatory formats may create problems later. Can IrfanView still open these compressed PDF files? IIRC PagePlus cannot open such PDF files for editing. Attach a small sample for testing if you like.

[SUDHA AGRAHARI]

I need to decrease the size of file to 100 KB or less.

[JendaLinda]

The program compresses all pictures in the pdf file with the JPEG2000 (color pictures) or the JBIG2 (b/w pictures) compression

Also JBIG2 has serious flaws, so nobody should use it.

[Bhikkhu Pesala]

Saving each page as a low quality WebP image may achieve usable results. JPG of very low quality to get below 100K at 256 colours gives poor results.

[insectinegate]

Also JBIG2 has serious flaws, so nobody should use it.

If you mean the old Xerox story, it's just a local bug there.

It's too bad JBIG2 doesn't get better visibility, and standalone image viewer codecs.
It's the best comperssion for 1-bit color / scanned documents.

[JendaLinda]

JBIG2 is a proprietary format, so the usability is limited. JBIG2 uses lossy compression, that's why it's more efficient than other codecs. JBIG2 is still flawed because of the unnoticeable compression artifacting. Instead of simply blurring or distorting the image it changes contents of the document, that's unacceptable.