Electronic documents can be saved in various formats, one of the most popular worldwide - PDF (Portable Document Format). The format was developed by Adobe Systems and is designed to store and present textual and graphical information in electronic form. You can work with documents through the official Adobe Reader program, as well as other third-party software. Today, many manufacturers of printing equipment support PDF at the hardware level, which allows you to print documents without using any additional software. The format is universal, and files with the extension “.pdf” are displayed in the same way, regardless of the device and the tool with which you open them. For documents, it is possible to set different levels of access, which is very convenient, and apart from other advantages, files are compact and do not take up much space by modern standards. However, sometimes users still need to compress documents so that they take up even less disk space. The PDF format has nothing against it and is subject to compression by various means, as we will do below.
PDF file compression methods.
What you need to reduce the size of the documents
The PDF format is used quite widely for various purposes, including in professional activities, for home use, it can often be used for study, so that files can sometimes be quite impressive in size. You may need to compress a PDF document for various reasons, for example:
- Free up disk space (in some cases, the lack of memory is really a problem and it goes into megabytes).
- In order to transfer files. Sometimes in order to send a PDF, the document needs to be reduced, since many web sites, email clients, programs do not accept dimensional files and there is often a limit to the allowable amount.
- Increasing the speed of opening a document (on low-powered devices, weighty files open much slower).
In such cases, compression usually comes to the rescue, and it is easy to do so even with minimal computer skills. Automating processes in programs and services today allows you to perform various tasks that would require more time and knowledge when performing the same actions manually.
Variants of how to compress a PDF file
There are several ways and even more tools that can be used to compress PDF files. You can apply any convenient options available. Consider how to compress a PDF document using various methods.
The oldest method of compressing information that has been used for decades and has not lost relevance today is to add files to the archive. Using standard archiver programs, for example, WinRAR or 7-Zip, you can change the size of the PDF file and save disk space, or collect several documents in one archive file, which will greatly increase the efficiency of data transfer to another device. Send an object to the archive is very simple. Consider the example of free software 7-Zip (the program must be available on the computer to perform the procedure), as by archiving to reduce the size of the PDF file:
- We select the necessary file, by pressing the RMB we call the context menu.
- We find in the list of options 7-Zip and click "Add to archive ...".
- In the opened window the settings are available. The minimum setting involves selecting the format and level of compression, after which we apply the changes by clicking "OK".
The same procedure can be done in WinRAR:
- The utility window displays the file system of the device, select the folder to create the archive and click "Add."
- In the settings menu on the General tab, select the compression method.
- Go to the “Files” tab and add the documents to be archived, then apply the changes.
The file will not lose quality, and after unpacking it will be available in its original form. In addition, using the archiver program, a large file can be divided into several parts for mailing, because many mail clients are not able to send voluminous documents, and the recipient will be able to assemble these parts into a single whole by extracting.
Compression using quality reduction (DPI)
DPI is the number of dots per inch (Dots per inch), one of the parameters used to indicate the resolution of image conversion processes. The greater this value in the characteristics of the image, the higher the quality, and the density of dots will also affect the size of the object. Therefore, you can reduce the weight of a PDF file by saving it with an indication of a different number of dots per inch. The decision to compress the object in this way is quite effective in the case of bulk scanned documents.
Decrease in quality is not always noticeable to the eye, since it is believed that a person is not able to see more than 300 dpi (what the standard in polygraphy is based on), so most often when changing DPI, you cannot determine the difference visually. As the quality further increases, only the file size will grow, and printing an image with a high DPI value is noticeably slower. If images are supposed to be displayed on a monitor, you can scan (or reduce documents) with a resolution of up to 72 dpi (web standard), since the monitor will not display more, and increasing the number of dots will only increase the file size, for this reason also harder to handle. You can manipulate changes to this parameter using various software, such as Adobe Acrobat, Fine Rider, Libre Office, Cute PDF Writer, etc.
Let us consider how to compress by decreasing the dpi PDF file using the Draw tool from the Libre Office suite:
- Run the software and in the main menu, select the option "Drawing Draw".
- Open the PDF document in the program and in the menu "File" click "Export to PDF ...".
- In the parameters window that opens, you can change the compression level, quality, including resolution (DPI), as well as other settings.
- When the parameters are specified, click the "Export" button, which allows you to create a new document with the current settings.
Another tool for working with files of this format Cute PDF Writer is to create a string when printing a document with the specified compression characteristics. So, to reduce the number of points, perform the following actions:
- After installing the software from the official site on the device (install both available files), you need to open the PDF file using any program that reads the format (for example, Adobe Reader).
- Call the print option (from the application menu or by pressing Ctrl + P).
- Now in the printer selection line we specify Cute PDF Writer, to the right of it click “Properties”.
- Open the tab "Paper and print quality", click "Advanced ...".
- In the new window, you can set the print quality in DPI, as well as set other parameters.
- After completing the necessary settings, click "OK" to apply the changes.
- Now we carry out "Printing", thus, saving the resulting PDF file in a different quality.
The object format during the procedure does not change, you only change the content's DPI, while reducing the file size, sometimes you can greatly reduce the quality, which in certain cases is unacceptable, for example, when working with images in high resolution.
Convert to DjVu format
Another way to compress an electronic PDF document so that it weighs less is to convert it to another format, namely DjVu. The lossy compression technology provides even more file compression than is offered by the PDF format. So, without reducing the DPI, we get a similar object of a smaller size. You can convert using special applications or online services (see below). For example, you can use a simple and convenient PDF to DjVu converter. It is easy to perform the conversion using the utility; to do this, you need to specify the location of the source file, as well as the path where we will save the resulting object in the new format, and then set the necessary conversion settings (you can leave the default settings). In this way, the files are compressed quite well, but the quality is lost during the conversion process, so this solution may not always be optimal. Conveniently, the object can be opened in programs that support the format, without the need for extraction, as is the case with archives.
Use of online tools
A quick and convenient way to perform compression so that the PDF file weighs less, without installing software on the device. There are a lot of services that can carry out the procedure online. Consider some of them.
I Love PDF
Excellent service with a wide range of tools for working with PDF. You can compress, convert to various formats, merge, split items and other actions. You can reduce the size of the object without losing quality. Compress PDF using an online service is very simple:
- Add a file (press the red selection button to load from the device, or using the add buttons from Dropbox, Google Drive, download from the cloud, you can also drag items to the appropriate area).
- When the object is added, you can choose the compression ratio settings or leave the recommended ones.
- Click the button "Compress PDF".
- After the procedure on the new page you can download the finished file. The weight of the object will be less, at almost the same level of quality.
PDF file size changes, as well as other actions with the object, can be performed using the online PDF2Go tool. The service offers many tools for editing, compressing, converting and other means of working with PDF. To reduce the weight of the document in this way:
- By analogy with the previous service, the item is added from the computer by pressing the select button, it is dragged to the specified area, downloaded from the cloud (Dropbox, Google Drive). In addition, you can specify a link to the file you want to convert.
- Now in the compression settings, select the required quality from the drop-down list. It is also possible to convert color pages into a black and white version (if required, mark this item).
- We press the green button “Save changes”.
Another good service for performing PDF compression and other tasks (editing, converting, splitting or merging files and others). Working with the tool is also easy, in the compression section we do the following:
- Select a file from the device, load it from the cloud, or drag an object to the appropriate area.
- Waiting for the completion of the compression process, you will see how the file was compressed, and you can download it.
The online service allows you to convert documents from PDF to DjVu, as well as simply compress them, leaving them in the same format. You can finish the object from the device, Dropbox, Google Drive or specify a URL, and when the process is complete, you can download or send the results to the cloud storage. In addition to working with PDF, this service is capable of converting elements of various formats (audio, video, images, documents, archives, presentations, etc.). There are many resources online that allow you to work with PDF online. Some of them have limitations on the size of the downloadable file (for example, up to 50 MB, 100 MB), others do not, but all online services work according to the same principle: load the object, perform compression settings and be content with the result. The interface is intuitive, so that difficulties in working with tools will not arise even from an inexperienced user.
Programs for working with PDF files
You can also reduce the weight of a PDF document using programs that require installation. In some cases, this method will be more convenient for the use of online services, as it is possible to work in the absence of the Internet.
You can compress a PDF document to the desired size in the following way:
- Open the object in Acrobat and in the menu "File" select the option "Save as another" - "PDF file of reduced size ...".
- Now you should select the version of the program from the available list so that the document obtained as a result of the procedure is compatible with it. When selecting the most recent item may not be available for previous versions. Click "OK".
- At the end of the process, you can save the result by specifying the path.
An alternative option is to choose from the File menu the option “Save as another” - “Optimized PDF file ...”. Thus, when reducing the size of an element, you can adjust the necessary compression parameters in detail.
The program allows you to create PDF files from virtually any application that supports the print function. The software has no graphical interface and acts as a subsystem of the printer, installing a virtual printer on the computer. In addition to converting objects to PDF, it is also possible to compress the finished elements, for which we perform the following actions:
- Open the document in Adobe Reader, where in the menu "File" choose "Print".
- In the print settings window, select CutePDF Writer from the list of available printers, click "Properties" next to this line.
- In the next window, click "Advanced."
- Among the additional parameters we find “Print Quality”, here in the drop-down list you can reduce DPI. For example, lowering from a high value to 300dpi, you will not notice a difference visually.
- Having set the required number of points, click "OK", then "Print" (this is how the document is saved, not printed).
Advanced PDF Compressor
The functionality of the application will reduce the size of the selected PDF document, convert images to PDF, combine objects. The compressor also has the ability to create profiles with different parameters, which is convenient when the program is used by more than one user, the same option can be used to switch between the created parameter templates. As for compression, there are settings for color and black-and-white documents. In the first version, it will also be proposed to change the color depth and simplify the image. It is possible to adjust the compression in percentage terms, but you should not get carried away, otherwise the result will not be quite similar to the source.
Free PDF Compressor
With this tool you can only vary the size of the PDF, for which the software has several ready-made settings templates with different quality parameters. The compressor interface is simple and straightforward, you just need to specify the source code, select the path to save the result and check the desired settings option, and after pressing the corresponding button, the process will start.
We looked at several effective methods for performing PDF compression. Whatever way you use to reduce the weight of documents, each of them is convenient and good in its own way, it all depends on the individual requirements for the result.