Compression is an inevitable process when file numbers or the file size is too large. Large files take a lot time to upload or download and are difficult to attach in e-mails. PDF, the most used format for transmission can be compressed easily. There are many types of software available for PDF compress free to download. This software is available on the internet, free for download.
The PDF compress free software can make use of different types of algorithms for compressing the files. LZW, FLATE (ZIP, in PDF 1.2), JPEG and JPEG2000, CCITT, JBIG2 compression (PDF version 1.4), RLE are some of the algorithms used by PDF compress free to download software. The two major classifications are the lossy compression and lossless compression. The main difference between the two types of compression is the compression ratio. The lossy compression algorithms can create files with greater compression ratio than the lossless. Another difference between the two is that the quality of the content in the lossy compression will be lesser when compared to lossless format. The factors likely to be compressed are image type, its resolution, font and how the fonts are embedded. The version of PDF and the compression level are also considered by these software.
To perform the PDF compress free of cost, PDF optimizer can also be used. By clicking on the Audit Space usage button in the advanced option, the unnecessary space usage in the PDF can be found. By saving the file using the Save As option, some of the unused elements in the PDF can be removed by overwriting the file on top of the existing one. Using the Save option will increase the file size. Mainly the images that are compressed by the software will decrease the file size in a huge way. The images, already compressed by image editing software, when added in the PDF, will be compressed by the software. The embedded font, which occupies large spaces, can also be removed. Subset fonts can be added can minimize the font and further compress PDF.