Re: Poor Graphics in Acrobat 5.05

["Thomas Michanek" <thomas.michanek@xxxxxxxxx>]

> I've been capturing most of the dialogs on a 1024x768 screen
> using Paint Shop Pro 6's Screen Capture utility. Following capture and save
> to PNG, the Information dialog box says that their resolution is 96 pixels
> per cm.

I guess you mean 96 pixels per inch? You really shouldn't pay much
attention to the resolution information in PSP. Most bitmap image
formats don't specify any resolution; they are simply a collection
of image pixels. The "resolution" of a bitmap only comes into play
when you import a bitmap or print it out, i.e. when you specify its
actual size on screen or on paper. A bitmap image does not have a
resolution in itself, despite what most people think.

> The images are from sharp in the PDF.

I interpret that as "far from sharp". By default, Acrobat (Reader)
has a setting "Smooth text and images" turned on, which makes bitmap
images less pixelated and more fuzzy. You can turn it off, but you
will hardly get "better" appearance on-screen. Depending on which
DPI you imported a graphic with in FM and the zoom setting in Acrobat,
you will get different results. A 72-dpi image displayed at 100% zoom
will look crisp in Acrobat, but as soon as you change the zoom, the
bitmap image needs to be resized, which cannot be done without effects
like "jagged" edges or "blocky" squares, unless you let Acrobat smooth
the image. This is an inherent property of bitmaps, which applications
solve in different ways for on-screen display (FrameMaker has no
smoothing of bitmaps, unlike Word or Acrobat).

This is only a display phenomena; printed output should be fine.

> During distilling, I turned off
> Downsampling and use ZIP 8-bit compression.

Good choices, exactly the ones that will leave bitmaps alone :-)

To summarize, the on-screen appearance depends on the settings used
in Acrobat (Reader), which you really cannot control. If you like,
settle on 72 or 144 DPI import in FM and hope the users will use
zoom levels of 50, 100 or 200% in Acrobat...


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Thomas Michanek, FrameMaker/UNIX/MIF expert
Technical Writer, Uppsala, Sweden
mailto:Thomas.Michanek@telia.com
http://go.to/framers/
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