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>One thing that has me puzzled is that SnagIt's resolution setting doesn't
>seem
>to affect what I think of as resolution at all -- it simply makes output
>(depending on the application) a different size. This variable does seem to
>be dependent also on file format, but I still haven't figured out entirely
>how.
Jennifer,
this is an explanation of bitmap graphics that I wrote as a response to a
different question but that you may find helpful (what is said regarding
FrmaeMaker is valid for PageMaker as well):
---------
When you are working with bitmap images, you must be aware of their
nature: Bitmap images (e.g., BMP, Tiff, JPEG, Gif, PNG) are nothing more
than mosaics, like those im Roman villas. The image consists just of a
fixed numbers of pixel rows, each containing a similarly fixed number of
individual pixels.
The resolution you give to such an image in FrameMaker is nothing more
than a scaling directive. When you tell FM that you want a 72-dpi image,
you say: "Make each pixel 1/72th inch across." When you specify 600 dpi,
you say: "Make each pixel 1/600th inch across." The number, color, and
arrangement of the pixels always stay the same. So it is no wonder that
FM gives you very small images - you told it so!
(And, no, what you really wanted is not possible: You cannot improve the
quality of a bitmap image by increasing the number of pixels in it. This
is flat-out impossible, no matter what tool or technique you use, short
of manually repainting the image.)
The bluriness you compain about has a related reason: The screen itself
is nothing more than a bitmap, i.e., it has a fixed number of pixels to
play with. Let's look at what this means for displaying screenshots:
Say you have taken a screenshot of 100x100 pixels and saved it as a
bitmap file that you import into FM. If you specify the nominal
resolution of the screen when importing the image (on Windows, usually 96
dpi), FM displays the image at original size - everything looks just like
the original screen you captured. The image takes up 100x100 screen
pixels in the FM file (displayed at 100% zoom factor).
When you now specify a higher resolution, there is a problem. For
example, you specify 192 dpi (other resolutions pose the same problems
invarying degrees): This means that the image is half as wide and half as
high on the screen - in other words, it must be displayed in a quarter of
the screen pixels - 50x50. And since screen pixels cannot be subdivided
(i.e., you cannot cram two pixels into one), FM must throw away three
quarters of the pixels in the image. (They are not really thrown away,
but they cannot be displayed at this zoom level.) There is no way to do
this without losing sharpness, which is why the image is "blurry".
This blurriness, however, is restricted to the screen. If you print the
page, the image looks sharper again, because the printer has many more
pixels to devote to the same area than the screen has. The bluriness also
goes away if you zoom in, again because more screen pixels can be used
for displaying the image.
---------------
Redux: Do not mess around with the resolution in SnagIt - it doesn't
change a thing. Simply resize the images as required in PageMaker. Also,
the format you are using is largely immaterial for the qualtiy of
screnshots, with two caveats:
- Do not use JPEG, it can impact the quality if you do not know what you
are doing.
- If you need more than 256 colors, do not use GIF.
For importing into PageMaker, Tiff is probably your safest choice. And
remember that the display quality onscreen is not necessarily the same as
that of the printed output.
Hope this helps
Jan Henning
--------------------------------------------------------------------
Jan Henning
ROSEMANN & LAURIDSEN GMBH
Am Schlossberg 14, D-82547 Eurasburg, Germany
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