Optimization, Color, and Transparency

Understanding Transparency

Guide to Optimization

Document size directly impacts processing time. Optimizing your document can improve the processing time needed to print your document.

There are three main issues that effect image size:

  1. Flatten File Layers. Images and text stacked on top of each other have additional file information that is not needed during printing. Flattening layers removes the information under the stacked layers so that the print only has to process the visible information. Layer transparencies may also need to be applied to completely flatten image layers, (see FAQ: Transparency, for more information).
  2. Reduce Color Resolution. There is very little noticeable difference between color images printed at 150 dpi and those set to anything higher than 150 dpi. By reducing your color graphics to at most 150 dpi, processing time can be reduced considerably. Use “Bicubic Downsampling” rather than “average” for best results.
  3. Compress Images. Image compression may need to occur for documents that exceed the acceptable file size for the current Output Room printer models. If compression is necessary, JPEG compression can be applied starting at maximum (which will remove color information outside the range of normal human vision). Maximum and high settings should be safe to apply without changing color values significantly. Consider other optimizing methods before applying compression settings below the medium quality setting. Compression options such as ZIP or LZW, which require further processing during print time, should not be used.

We recommend that you address these issues just before printing, when saving your design as a PDF. This will give you more flexibility during the design process and give you some device independence if you later choose to output your file to another device with different capabilities. [NOTE: When using our large format printing service files need to be saved in a PDF/X-3 file format. See Submitting Jobs for Print].

Acrobat Professional has a great tool for assisting you to reduce the size of your PDF prior to printing.

For some additional information regarding PDF optimization visit:

Acrobat PDF Optimizer Review (version 8).
How to Reduce PDF File Size (alternative methods)
Optimize a PDF – Adobe Web Help
How to optimize your PDF File (video tutorial)

Understanding Color Management