The size of Portable Document Files could be relatively smaller than its counterpart, PostScript files. This possibly happens with the help of improved data structure but even more than that it is the efficient compression algorithms in PDF that support this. Compression algorithms’ list that could be used is of a wide range as given below:

  • CCITT G3/G4- It is brought into usage for monochrome images or pictures.

  • JPEG- Again used for images.

  • JPEG 2000- This one is a more updated alternative to JPEG which as well is used to compress images.

  • Flate- Text as well as image compression could be done.

  • LZW- This gets replaced by Flate else for text and image compression it is used.

  • ZIP- This is used for color and grayscale images.

Read further to get a better insight at how it wor

ks.

Given that compression is switched in Acrobat Distiller then this would first decompress all images in PostScript and then again compress them when creating a file in PDF format. In a few cases you could open a text editor that is capable at handling data (TextPad, UltraEdit) and then look for the ‘Filter’ keywords. CCITT compression in files with this format could be used for black and white images. It is the similar algorithm that is utilized in fax equipment. CCITT group 3 or 4 compressions are offered by Acrobat. A majority agrees that group 4 is better to be used. Leaving it switched on all the time is very much possible. Talking about Flate compression, it at times is called as deflate, is a rather complex compression algorithm.

For CCITT compression’s monochromatic black and white images, there is an alternative to it which is JBIG2. A few are of the say that implementation in Acrobat is more sluggish than CCITT G4 compression which may be one reason hampering people from using it much. As far as JPEG compression is concerned, it could be both lossy and non-lossy. Only lossy is the one that is available in Acrobat which means that a few of the details of images could be lost when compression process is carried out. So it is simple to understand that the more you compress the more details you lose from the file. It is a common practice to convert pdf to word so as to edit the pdf document. For the 4 onwards categories in Acrobat Distiller, there are 5 various levels to compress. Compression of the already compressed files would lead to added loss of data. So, it is always better to be careful when handling compression here.