Acrobat Flate Compression
Acrobat uses flate compression for PDF files that have their object streams individually compressed. Flate is an improvement of LZW compression, it is both more efficient and royalty free. Being able to read huge PDF files in plain text makes extraction, program analysis, and new software design possible. The flate compression operation is found in the PDF Reference Manual and the PostScript Reference Manual from Adobe Systems. Flate works well on images with large areas of single colors or repeating patterns.
Flate Compression Filters
Flate compression filters look at incoming requests if the Accept-Encoded headers contain gzip or deflate then the files are compressed. Once the server has prepared a response it is compressed then sent to the browser. These filters are made to work in default mode so no registry settings are necessary. Some of the filter behavior can be changed by registry settings.
Flate Compression and PDF
The flate compression methods for PDF are based on the public-domain zlib/deflate compression, either involving binary data or ASCII text. Binary data is always produced regardless of the text. Flate encoding output is usually very compact when compared to other methods used. Flate compression allows better user experience with different settings to work for different functions. You can select the actual compression type, image size, quality options, size option for color, and grayscale and monochrome images.