It is possible to compress PDF documents in order to reduce the file size and thus lowering storage or transportation costs. The Black Ice PDF Printer Drivers support different industry standard compression formats for the different parts of PDF documents. The compression formats to use may be freely selected by the user in the printing preferences.
Under the compression tab you can select the compression algorithm of the PDF document’s content. Using compression will reduce the size of the output file. Compression method uses a formula or algorithm to compress data. This algorithm determines the compression quality.
A compression algorithm can be as simple as removing all extra space characters, inserting a single repeat character to indicate a string of repeated characters, and substituting smaller bit strings for frequently occurring characters. Even this kind of compression can reduce a text file to 50% of its original size.
Compression can be either lossy (some information is permanently lost) or lossless (all information can be restored). Black Ice Printer Drivers provide the following compression methods:
- Stream Compression Filter: PDF files store most of the embedded data (such as page descriptors, fonts) in streams. All streams in the document support compression. Setting stream compression formats effects documents the most which use lots of text or 2D vector-graphical content and few raster images
- Color Raster Image Compression: The compression type to use on any embedded color raster image. Using the JPEG compression for example, which applies only for color image formats will greatly reduce file size when using many images in a document at the expense of some quality loss.
Quality: Quality of the JPEG compressed images (available values from 1 to 100, where 100 is the best quality)
- Monochrome Image Compression: Different compression formats may be used specially for 2 color image formats, i.e.: the CCITT Fax compression format, which offers a great compression ratio but only for monochrome raster images.
None - no compression algorithm will be used
Flate is a lossless compression method. Flate works well on images with large areas of single colors or repeating patterns.
Run Length Encoding (RLE) is also a lossless compression option that produces the best results for images that contain large areas of solid white or black.
JPEG is a lossy compression algorithm that has been conceived to reduce the file size of natural, photographic-like true-color images as much as possible without affecting the quality of the image as experienced by the human eye and nervous sytem. JPEG is suitable for grayscale or color images. Because JPEG eliminates data, it can achieve much smaller file sizes than other lossless compression methods.
CCITT Fax is also a lossless compression option. CCITT stands for “International Coordinating Committee for Telephony and Telegraphy”. CCITT Fax compression is the appropriate compression method for black-and-white images made by paint programs and any images scanned with an image depth of 1 bit.
LZW Compression (Lempel–Ziv–Welch) is a universal lossless data compression algorithm. LZW compression became the first widely used universal data compression method on computers. A large English text file can typically be compressed via LZW to about half its original size. LZW became very widely used when it became part of the GIF image format, and it also used in TIFF and PDF files.