User Guide

PrimoPDF Version 4.0 User Manual

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• Don’t downsample. With this option selected, PrimoPDF does not downsample the images in

your PDF file. This option produces the highest quality of output, and should be used if you

are creating PDF files for printing to a commercial quality printer.

• Average. When average downsampling is selected, PrimoPDF averages neighboring pixels,

replacing pixels of similar value with the average pixel color. Averaging generally produces

good quality results and is suitable for printing to most desktop printers.

• Subsample. Subsampling means that PrimoPDF takes a pixel from a sampled area and replaces

the entire area with the selected pixel. Subsampling results in smaller file sizes and faster PDF

creation, but you may notice a decrease in visual quality.

• Bicubic. When bicubic downsampling is applied, PrimoPDF uses bicubic interpolation to

generate new pixel values. In plain language, PrimoPDF applies a special averaging method to

the image to create the highest quality possible. The bicubic option can create more pleasing

results than other subsampling methods, although the PDF file is slower to generate.

Downsampling Threshold. Reduces image resolution to assist in reducing the PDF file size. You can

establish a monochrome image resolution threshold. Any images having a resolution above the value

specified will be downsampled to the resolution specified.

Compression. Set the compression filter for monochrome images:

• CCITT (International Coordinating Committee for Telephony and Telegraphy) Fax Encoding.

This is a lossless compression method that uses standard fax compression and only applies to

black and white bitmap images.

• Flate Encode. Uses the ZIP compression method to reduce image size without affecting the

image’s quality.

• Run Length Encode. A form of compression that is particularly effective on files that contain

many long runs of the same byte, value, or character. It is primarily used on binary files.