User Guide

PrimoPDF Version 4.0 User Manual

Page 14 of 16

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

establish a color image resolution threshold. Any images having a resolution above the value specified will

be downsampled to the resolution specified.

Convert CMYK to RGB for onscreen viewing. Converts color images from the CMYK color model (used for

printing) to the RGB color model (used for onscreen display).

Grayscale Image Settings

The Grayscale pane enables you to set options to be used in creating a PDF that contains grayscale images.

Figure 18. Grayscale Images

Downsampling. Downsampling is used to help reduce the size of your outputted PDF file. It allows you to

optimize the images in the PDF to achieve the best balance between visual quality and file size.

Downsampling reduces an image’s resolution (to the resolution specified) by discarding pixels. Since there

is less information that needs to be saved, the resultant PDF file sizes are considerably smaller.

NOTE: If you are using a downsampling technique, you need to specify the desired resolution for the

outputted image. Resolution is measured in pixels per inch (PPI).

PrimoPDF has four options for downsampling grayscale images:

• 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.