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 29 
Optimally display screen captures
For a screen capture to look best at a
zoom level of 100%, it has to be incorporated into the page (at
the authoring stage) with a resolution of 96 dpi (Acrobat 6 and
higher). The screen capture will then be displayed as intended
at a zoom of 100%, and with the least distortion at zoom multiples
of 50%. Magnification settings such as Fit Page or Fit Width
yield unpredictable zoom levels, and therefore unpredictable
display quality of screen captures (due to dynamic on-screen
downsampling/upsampling). This is particularly evident in the
text in screen captures.
In screen-optimized PDFs (and when printing
the PDF is not the primary intended use), a separate PDF ("image
viewer") can 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; Example (PDF: 53K) and a linked image viewer (PDF: 48K).
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). This example also takes into account the different
display resolutions of Acrobat/Reader 6 (and later, 96 dpi
by default) vs. Acrobat/Reader 5 (and earlier, 72 dpi).
Another screen-optimized approach: JPEG
images displayed in a floating window (PDF: 33K), linked
or embedded (TimeSavers+Multimedia Assistant).
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