When the PDF is displayed on-screen, zooming in/out will effectively 
downsample/upsample the screen capture, causing loss of quality.

For an optimal display of screen captures (and when printing the PDF is not 
the primary intended use), a separate PDF ("image viewer") may be used, 
with a controlled default zoom level that is related to the dpi value used 
in FrameMaker. This default zoom level is restored, if changed, when the 
reader switches pages.

For an example, see http://www.microtype.com/showcase/text.pdf
The linked file -- http://www.microtype.com/showcase/screens.pdf -- takes 
into account the different display resolution of Acrobat/Reader 5 (and 
earlier, 72 dpi) vs. Acrobat/Reader 6 (and later, 96 dpi by default).
If you open the screens.pdf file in Acrobat/Reader 6.0 or higher, it opens 
at 75% zoom. Display quality is the same as the original (assuming that 
Acrobat's default display resolution of 96 is in effect). When you change 
the zoom to 74%, 73%, or 76%, loss of quality is immediately visible 
(missing pixels or blurry areas).

Magnification settings such as Fit Page or Fit Width yield unpredictable 
zoom levels, and therefore unpredictable display quality of screen captures.

[ Another screen-optimized approach is demonstrated at 
http://www.microtype.com/showcase/MultimediaAsst/Jpeg_linked.pdf ]

Shlomo Perets

MicroType, http://www.microtype.com * ToolbarPlus Express for FrameMaker
FrameMaker/Acrobat training & consulting * FrameMaker-to-Acrobat 

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