To choose the right PDF compression method, you need to understand how this file was created and what it contains. The amount of work that needs to be done is also important. Do we need to compress just one page or an entire book? Let's look at all the options:
- A PDF file is a picture that does not contain text. For such files, online services may quite well be able to “compress” pictures quite effectively.
- PDF or Word file saved in Excel. Microsoft Office does not save much when writing PDF files, and the easiest way to compress such a document is to use an online service.
- A document from a scanner that contains text (for example, a contract). To compress such a file as much as possible, you must first recognize all alphanumeric characters using special programs and save it in the same PDF again.
Compress PDF Online: Online Services Efficiency
To get started, just create a PDF. For those who may not know, let's look at how to create a PDF file from Word or Excel.
Create a regular Word file, let it be a contract. Open File - Save As, then in the File Type cell (Word or Excel by default), select PDF and save.
Microsoft is not saving. This Word file is 117 KB in size, and 412 KB in PDF format. We will use the online service to compress our document.
The online service has compressed PDF to 123 KB. A decrease in quality that can be noticed has not occurred. There are many such services on the global network.
But what if the entire document is a picture, for example, a scan copy of the contract, and it needs to be sent by mail, but it is very large? How to reduce the size of a PDF file as much as possible so that it can be sent quickly via e-mail?
For example, consider the most difficult case. We take a picture of the spread of the book and try to reduce the size of this JPG file to a minimum. The photo was specially taken in poor quality, with distortion, to show how this can be fixed in the program. Nevertheless, try to get a high-quality copy from the scanner or take a picture smoothly, without distortion, with good bright lighting.
A single page spread photo in JPG format takes 2741 KB. Convert JPG to PDF using online services.
Now our picture in PDF format occupies 318 KB.
Great result, but how to reduce the size of PDF even more? Very simple! You need to recognize the text. Photos take up a lot of space, and as long as the spread of our book is a picture, it will occupy disk space, because every pixel is saved, but we are not interested in all the pixels, we are only interested in the text. In order for the PDF file to cease to be a picture and become text, it must be processed with a special text recognition program. You can also find online services for this. To reduce the size of the PDF, the program recognizes alphanumeric characters and saves them as text, not as a picture. But online services do not give us full control over the document.
Efficiency of PDF recognition and compression programs
To recognize Slavic languages (Russian, Ukrainian, Belarusian), they most often use the good old ABBYY FineReader Professional, which can work even from a flash drive. That is, FineReader can be installed on a USB drive, which makes it possible to run this program on any computer.
How much can a PDF file be reduced with FineReader?
After recognizing the text and saving it again in PDF format, our photo spread of the book takes 62 KB. In this case, a noticeable decrease in quality is not observed. You can experiment further and try to compress this already recognized PDF file in online services again. After compression, it began to occupy 56 KB.
Thus, a JPG file occupies 2741 KB, and a recognized PDF file takes 56 KB. That is, we received a photograph without a noticeable decrease in quality with recognized text and a much smaller size. If we have only one page, then studying the whole program for this does not make sense. But how to reduce the size of a PDF document if we have a large book and it should not take up too much space on the computer?
How to use pdf recognition software?
As soon as you open the file in the program interface, the recognition process starts automatically. Recognized text, pictures, tables, footers, etc.
If the text is not important to you, then you can simply save the recognized file to PDF.
Text recognition programs are also able to receive files from the scanner. Open FineReader and click on the "Scan" button. The image will be displayed on the monitor screen and the document will be recognized. Then you need to save the file in PDF format.
If the text is important to you, you can correct minor errors in the right panel, if they are not very many, and save. Files can be created not only in PDF format, Word, Excel and others are also available.
If there are many errors, you can edit the document to improve the "visibility" of the text for the program. To do this, click the "Edit" button in the upper toolbar.
File Editing for Better PDF Recognition
The first on the list that we are offered is “Recommended Processing”, where the program itself will determine how to reduce the size of the PDF and what needs to be done.
The Keystone function may be useful if your photo was taken at an angle and you need to align the text.
Result:
Use the Correct Line Distortion feature to further align text.
If you add brightness and contrast, it will be easier for the program to recognize all areas correctly with black letters and a white background.
All this can be done very quickly, much faster than manually rewriting the text. Aligning the page and increasing contrast helps the program better "see" alphanumeric characters, and you do not need to rewrite the text and save it in any format convenient for you.
Clear and reduce PDF file format
The Eraser function is very useful, it can remove debris and dirt from the page if you scanned the contract and want to send it to someone by e-mail. It will be unpleasant for people to read a document on which there are some strange points, spots, etc., so we remove the dirt from the Eraser page. If you need to remove prints, signatures with a colored pen, and other color images from images, there is a very useful function called “Delete color elements”.
Very often you have to use the “Break” function. This function can split the page into two parts horizontally or vertically.
In many documents, text is present only up to half a page, and it is not very pleasant to turn over a PDF file in which there are a large number of half-empty pages. Therefore, it is better to crop such pages.
The "Crop" function helps to "cut" only the necessary part from the document. These features will help reduce PDF size if necessary.
Change and delete PDF recognition areas
You can also change or delete recognition areas. Change the type of region if it was not recognized correctly. For example, the program mistakenly recognized the area as a picture instead of text, then you can change the type of area from a picture to text and recognize it.
The area can also be a table, which can be easily formatted and then used as an Excel spreadsheet. It is also possible to specify the "Barcode" area, which the program successfully recognizes. It is very useful to label pictures as "background pictures".
How to reduce the size of PDF using background images?
If you do not need pictures, designate them as "background pictures", then they will take up less disk space than regular ones. For example, the document was printed on a color form and it is necessary that the quality of the form does not deteriorate, but it also does not need this picture to "take" a lot of memory or be displayed in Word or Excel documents. Then the color form is denoted by the background image. If you want the picture to be available in Word or Excel, leave it as a regular picture.
If you do not need color pictures, then save the PDF in black and white, this will help to further compress the file.
Add, delete, move pages inside a PDF document
Pages in the document you can add, delete, change their numbering and sequence, as well as much more.
This is the main thing that can come in handy to reduce the size of a PDF without losing quality.
After installing the program, you need to make minimal settings, for example, make an interface in Russian.
To do this, find the icon in the upper Tools panel (“Settings") and select "Interface language - Russian" in the window that opens.
You will find more detailed instructions on how to reduce the size of the PDF, configure the interface and make the most of all the functions on the official website, but only the most useful and often used ones are presented here.
Set the operations that the program will perform each time you open or scan documents. Sometimes it’s more profitable to run all the processes yourself, because the machine can “freeze” for a long time after each scanned page. To optimize the time, turn off the automatic recognition process. When the scan is over, start page recognition. While the computer “hangs” over this task, you can find yourself another occupation, because the processor will be busy and will not be able to perform other operations normally. It depends on how powerful your computer is, and this is important to consider.
Thus, we figured out how to reduce the size of a PDF document using online services and special programs. It remains only to choose the most suitable option for yourself.