PDF Compression and editing techniques - pdf

I am not sure this question belongs on a programming forum but then again not sure where it would.
I currently open any PDF documents in Adobe Acrobat 9 Pro when reading or editing files. Many times, I want to make a change to the text in those files and will simply use the Tools->Advanced Editing->Touch Up Text Tool to do so.
No issues with the actual text changes but when I go back to save the file, the file size increases drastically. Even after running Advanced->PDF Optimizer and Document->Reduce File Size, the size is still much larger than the previous file, in many cases even if I am reducing the amount of text on that page.
It is quite frustrating. I am sure entire books have been written about proper PDF compression but take one text only document I have for example: file size is 110KB for a 12 page document. We just migrated to Google Apps and an entire 72 page PDF was under 600 KB.
Am I missing something?

Save as... your document after some changes.

Sounds like the font data is being embedded into the PDF when you edit it. Run Acrobat's Space Audit on the original and modified PDF to determine what is taking up the extra space in the modified PDF.

Related

html to pdf is taking way longer than html to word

So I am trying downloading a 260 / 270 pages document, which is a little over 1 mb when downloaded as a document. When downloaded as a word document, it takes about a second, however, when trying to download the same as a PDF, it is taking an eternity.
Any idea why this is happenning, can the number of pages be a reason, and if so, any solution here?
You don't say enough about the context you're in - language, libraries, tools or whatever - to give a good answer.
However, I'd guess that the PDF is being generated as images, not as text, and so the massive increase in file size (assuming that is what you mean by taking an eternity).
If you have control of the environment - use a better tool/library to render the PDF. PDF is perfectly capable of rendering text and graphics as such. If you don't control it, either complain to the vendor or make a cup of tea!

How can I edit the search text of a searchable PDF?

I have access to a scanner at my library which can create "searchable PDFs." These are PDFs that show the exact image of a scanned document, but there is a kind of hidden text in the PDF that can be selected when you try to select a portion of the image that contains text. In this way you can copy and paste text or search for text in the scanned document. This is VERY useful. It's an awesome improvement over raw scanned images. I also have several apps on my mac that can create this kind of searchable PDF from a scanned document or a raw image.
Now it's obvious from any who has ever used OCR that the process of converting images to text is not 100% accurate, so the text that you search or copy will not be correct in some places.
So I search for quite some time to find an application that would load a searchable PDF and allow me to repair the hidden searchable text without reformatting or modifying the original scanned image.
Does anyone know of a tool (or library API) that would allow this?
It's worth saying here that I tried the latest version of Adobe Acrobat DC for Mac, and it doesn't seem to even allow me to view the hidden searchable text, much less edit it. It does allow me to replace scanned image with the results of it's own OCR process so that I could edit and save the document. But this would produce horrible results for any of the scanned documents that I am using. It seems designed for editing a "native PDF" not editing a scanned document.
I have also tried ABBYY FineReader with no luck.
i'm using ABBYY FineReader 12 Professional. (not open source)
Just open a scanned image or scanned pdf and press Verify Text(or Ctrl + F7), than you go over all the spelling errors or low-confidence charachters and fix them.
The program is very good, it shows you the exact place in image/pdf to correct and the OCR guessing side by side for convenience. It iterates all of them.
[By the way, I'm using the shortcuts to speed up things:
Alt+Enter to add the unrecognized word to dictionary.
Ctrl+Delete to skip word or confirm in case you fixed it.]
Than save the document as a pdf file Menu:File>Save Document As> PDF File, and you can search it on every pdf reader. The saved file look the same as the scanned one, but 'behind' it there text.
It's weird you tried ABBYY with no luck... it's working great for me. maybe you tried not the Professional version.
Hope it helps you.
It is not creating a searchable pdf from images the poster is after, he wants to start with an already searchable pdf and modify its text (e.g. because intially a searchable pdf was made but later an overlooked error in recognition was found and needs correction). I see no way and no tool that assists in doing this.

Adjusting format of PDF to print it faster

I am using a combination of iTextSharp and PdfSharp to assemble a large PDF file for printing to a Canon Oce VarioPrint 6000 series printer. The PDF is replacing a postscript file.
Both this new file and the old are transferred to the printer via an LPR command.
The postscript file would take maybe 10 minutes to rip to the printer. My PDF version of the same file is taking over 30 minutes to process before it is ready to print.
Can anyone give me pointers into ways I could change the way this file is written / created that would decrease the processing time on the Vario?
EDIT: I took the file that was ripping so slowly and ran it through Acrobat Preflight and it found many RGB images, that it wanted to convert to CMYK. When I look at the PDF though, they are all black and white logos, so I had Preflight do a fix up to convert all images to print Black and White.
I also noticed the Preflight was consolidating backgrounds. Half of the pages have the same logo on them, so leveraging this conversion is probably also helpful.
When I LPR'd that file, it copyed and ripped in less than 5 minutes! So I guess the real question is how can I do that programmatically?
I am modifying the title and tags.
Thanks!
An equivalent result to the preflight repair process in this case can be gotten by using iText (or in my case, iTextSharp). I replaced the PdfSharp method of aggregating the pdfs with the PdfSmartCopy class. This brought down the size of the outputted pdf significantly, combined with using iText's reader.RemoveUnusedObjects(), and my rip time to the printer was lowered to the same or below the previous rip times that we had with the postscript file. Very pleased.
So the RGB images that were probably contributing to the large processing time, were narrowed by the Smart copy removing duplicates.
More info on PdfSmartCopy can be found at: http://api.itextpdf.com/itext/com/itextpdf/text/pdf/PdfSmartCopy.html
and in Bruno's book, iText In Action, more specifically in Chapter 6.

Converting bitmap pdf to pdf with text that can be copied

In reading journal articles for school, I often come across pdfs where I cannot select text, which makes taking notes very inconvenient. The funny thing is, the pdf does not appear to be scanned, and the security permissions allow for copying, but the text does not enable me to do so. How can I convert this pdf into a pdf where I can select the text, preferably without having to convert each page individually, as there are typically 20 pages per pdf.
I've tried some online converters, but I can't seem to find one that can 'digitize' the text while maintaining the file in a pdf format.
Any suggestions? Any background information to explain this helps as well.
Thanks much.
Try to "print" the original pdf file into a new pdf archive by using "PDF Creator" or a similar application. In the new file you should be able to select the text.

PDF compression How does Adobe do it?

This is a bit more of a fun question than a serious one, but how does the Adobe PDF format make documents so... portable?
I just created a small Word document, 235kb in size, containing multiple color photos and a few textual phrases. A PDF created using CutePDF (which I understand isn't the most efficient method of PDF creation) is only 176kb. That's a 25% compression ratio. When those files are placed into a compressed folder, the PDF is capable of 3% compression where the .docx can only take 2%. I'm sure that larger files would have even greater differences in size.
My question is, how does Adobe manage to make their files so much smaller? I understand that they are drawn from raster graphics, but my 3 bitmap files really can't be helped from raster that much, can they?
If you have Acrobat 9 there is a nice tool built-in so you can see how the PDF was put together (and compressions used). There is a blog post explaining how to use it at http://pdf.jpedal.org/java-pdf-blog/bid/10479/Viewing-PDF-objects
There are a few ways it can be compressing this:
Pdf files use lzw and zip compression.
If the image is scaled in the document, or is a larger dpi on disk than you allow for in cutepdf (for example, if cutepdf is set for 300dpi and the image is 600 dpi), it can be scaled in the pdf.
Microsoft stores TONS of info in the docx format, in xml. WAY more than is really needed to just export the info (for an example, try copying and pasting your text into a textbox cell, and look at the html info that comes out - I had a limit on a textbox size for a cms, and a 7 word sentence ballooned to 950 characters). This is so it can be later edited, and with a lot of esoteric info to make sure everything displays right in every possible permutation. The pdf doesn't need that info, and so it can just do the font and size, and strip out all the unnecessary info, saving a ton of space.
When you use such small files any overhead in the document format will have a disproportionate effect which is why you are seeing such large % differences.
I took a 2683KB JPEG and inserted it into a new word 2003 document. The resulting .doc file was 2725KB (or 2697KB as docx). Turning this into a PDF gives me a 2701KB PDF. So I am seeing a difference of 25KB, but only about 1% difference because of the size of the image data. It is about half what you got but maybe the version of word you have is more verbose when making docx?
For the PDF, acrobat shows space usage as 2691K image, 8.27K overhead and 1K fonts. PDF is quite a sparse format in its syntax which limits overhead and much of it has repeating strings so is easily compressible.
If you want to see what the PDF contains in a tree-like view you can download the demo version of CosEdit.