Reducing File Size with Compression Options

Changing the compression options can have a large impact on the size of the file but care must be taken when choosing compression methods as the file contents can also determine how well the chosen compression method will work. For instance, full color publication from Microsoft® Publisher or similar will compress better using JPG compression than using Packbits because JPG compression was designed to compress images with lots of color variation while Packbits works best with runs of solid colors in the image.

The default compression methods chosen by PDF Image Printer upon install will often give a good balance between file size and quality. When changing compression methods, take care to note the settings on the following tabs. These settings will affect the color model of the output file, which controls which compression method is used.

 

the Color setting on the Paper/Quality tab

any Color Reduction settings on the Save tab -  reducing the amount of color needed to represent the image can also have a significant impact on the disk size of the resulting file.

if fax mode is enabled in the FAX tab

PDF Image Printer creates non-searchable, or image only PDF files. A non-searchable PDF file is a series of one or more images wrapped in a PDF document. This type of file is useful in cases where you don't want the information in the document to be easily copied or altered. A non-searchable PDF file is not guaranteed to be fully copy-proof but it is one more step towards protecting your document. PDF files can also be created that are PDF/A-1b compliant.

As each page inside the PDF file is an image, PDF Image Printer has several different compression options that are used to compress, or shrink, the images in the document so that the file takes up less space on your hard drive.

All of the PDF compression options are controlled through the Compression tab in the Printing Preferences dialog. Close any open applications that you will be printing from before making changes as not all applications will see your changes until they are re-started.

Modifying the compression methods using the following steps is a global change, meaning that all applications will use these options when printing to PDF Image Printer.

Step by Step Instructions

 

1.From the Start menu, go to All Programs - PDF Image Printer 11.0 - Properties...

2.Click the Compression tab in the Printing Preferences dialog.

Leave Standard to None or change it to PDF/A-1b to create a PDF/A-1b compliant PDF file.

In the PDF Compression section, change the compression method to use for each color model of PDF page as desired.

3.Click the Apply button and then the OK button to set the changes.

4.Printing to PDF Image Printer from any application will now use the compression methods chosen to compress the pages in the file.

PDF/A-1b Compliance

A PDF file created with PDF/A-1b compliance is meant for long-term archiving of electronic documents and ensures that the document is visually correct. When creating a PDF/A-1b compliant PDF file, all PDF security options are automatically ignored and any LZW compression is replaced with ZIP compression.

About PDF Compression Methods

By default, Compression is enabled for all PDF files created. Turning the compression options off will increase the size of your document.

The ASCII format compression option creates a 7-bit compressed PDF file; this option is rarely needed anymore and is only included for compatibility with older networks and e-mail systems. Leave this option unchecked to create an 8-bit compressed document.

The default compression methods chosen by PDF Image Printer upon install will often give the smallest file. When changing compression methods, take care to note any Color Reduction settings on the Save tab or the Color option setting on the Paper/Quality tab as these properties determine the color model of the file. Changing the compression method for Color Images to Medium Quality JPG when printing in Black and White or with Color Reduction set to Reduce to black and white will have no effect on the resulting black and white PDF file.

Low, Medium and High JPEG and the JPEG Quality Factor

When using JPEG compression, a quality setting, or Q factor is often used to determine the  quality and level of compression.

With JPEG compression, which is a lossy compression algorithm, a higher quality factor produces a better image but a larger file. A lower quality factor will produce a smaller file but the image quality can be degraded.

The Q factor used by PDF Image Printer is a range of 1 to 100 with the individual compression levels set at follows:

JPEG Low Quality uses a Q Factor of 30

JPEG Medium Quality uses a Q Factor of 75

JPEG High Quality uses a Q Factor of 85 (100 for grey or indexed compression)

 

Image Color Model

Compression Methods

Used When...

Text and Line Art

None

Run Length

Zip

LZW

Always when selected; not affected by the color mode.

Color Images

None

Low Quality JPG

Medium Quality JPG

High Quality JPG

Run Length

LZW

Color is chosen on the Paper/Quality tab and

Color Reduction on the Save tab is set to Reduce to optimal and there are more than 256 colors in the document

Color Reduction on the Save tab is set to None

Indexed Images

None

Low Quality JPG

Medium Quality JPG

High Quality JPG

Run Length

LZW

Color is chosen on the Paper/Quality tab and

Color Reduction on the Save tab is set to Reduce to optimal and there is less than 256 colors in the document

Greyscale Images

None

Low Quality JPG

Medium Quality JPG

High Quality JPG

Run Length

LZW

Color is chosen on the Paper/Quality tab and

Color Reduction on the Save tab is set to Reduce to optimal and there are only greyscale colors in the document

Color Reduction on the Save tab is set to Reduce to greyscale

Monochrome Images

None

CCITT Group 3 1D

CCITT Group 3 2D

CCITT Group 4

Black & White is chosen on the Paper/Quality tab

Color is set on the Paper/Quality tab and

Color Reduction on the Save tab is set to Reduce to optimal and there are only 2 colors, black and white, in the document

Color Reduction on the Save tab is set to Reduce to black and white

Fax mode is enabled on the FAX tab.