How Does PDF Compression Work?
There are several ways to compress a PDF file in order to decrease its file size and store more data in fewer bytes. For best results, PDF compression software use different ways to compress a PDF file that contains mainly text and one that contains mainly images. For example, PDF compression software may use ZIP compression for files that contain text and JPEG for files that contain images. The size of the PDF file after compression depends on your choice of the compression method, how well the compression method describes the data, and how complex the original PDF document is in terms of images, multimedia, and fonts.
Which are the Commonly Used Algorithms to Compress a PDF File?
Different ways to compress a PDF file are either lossy or lossless. Lossy algorithms provide better compression ratios because they selectively eliminate some information in the file. These algorithms are used for sound and image files. Lossless algorithms, on the other hand, leave the content of a file unaltered. If you compress a PDF file using a lossless algorithm and then decompress it, you will find that the file is unchanged. Lossless algorithms are used to compress a PDF file that contains text. Commonly used ways to compress a PDF file include lossless algorithms such as LZW (Lempel-Ziv-Welch), Flate, JBIG2, CCIT, and RLE, and lossy algorithms such as JPEG and JPEG2000.
How Do You Choose the Best Way to Compress a PDF File?
Various PDF compression software available as freeware or paid versions use different ways to compress a PDF file. When using these software, you need to choose between the various ways to compress a PDF file. If your PDF file contains images with large areas of the same color or patterns that are repeating, use Flate compression. You can also use Flate for images created with paint programs and black-and-white images. If your file contains photographs with continuous tone, use JPEG. Alternatively, you can use JPEG2000, which is the industry standard for compressing image data. If your PDF file contains monochrome images, you can use either CCITT G4 or Flate.