PDF24 Compress - the tool to compress PDF files
The PDF24 Creator contains the small but powerful tool PDF24 Compress that you can compress PDF files with. First, install the PDF24 Creator. The current version can be downloaded here. Open after installing PDF24 Compress. Now drag all PDF files that you want to compress into the file list. Your files will then appear in the list. The program compresses your files based on parameters that you can set in the main window. The compressed size is displayed in the file list. Change the parameters when the compression has not yet brought the desired effect, until the size of your PDF matches your requirements. The compression is applied to all files in the list.
What may also sometimes occur is that a file becomes larger. If, for example, you set a DPI number that is greater than the DPI number that the PDF was created with, then PDF24 Compress will apply your chosen DPI number and the PDF will get larger.
Which PDF files compress well
PDF files with images compress well, PDF files with text compress less well. For PDF files with images, the images take up the most space in the file. Images can be reduced in quality and also in size. Both measures lead to a PDF file losing size. In PDF24 Compress tool, it is the parameter DPI and image quality that need to be adjusted. You control the size of the images via the DPI number. You control the image quality with the compression.
What effects DPI and image quality
With the DPI (dots per inch), you control how much of the image pixels are present in one inch. At a high DPI number there are more pixels than in a small number of DPI. A high pixel density leads to great pictures. Images with a lot of information is always good if you want to enlarge the size. If the images are already large, then it must not be expected for them to be bigger. It is better to see photos that are still clean. For images with little information they are algorithmically enlarged which makes them unclean. Large images take up a lot of space. The DPI number should now be selected so that images from an imagined point of view (for example, the normal view on the computer screen) look good.
Regarding image quality, an algorithm reduces the quality of the images and thus information from the image. The compression is lossy and causes image distortions. In normal photos this is hardly noticeable, and therefore a person can make the biggest image compression by significantly reducing the image quality.