atw: Re: image file formats - suggestions wanted

>This is a screen shot made using SnagIt. I then add graphical elements
(numbers) and flatten the file before importing it into MS-Word (as BMP
currently).

It's important to understand the difference between vector and raster
graphic formats. (You'll have to look them up; Wikipedia looks OK at a quick
glance.) Vector graphics are usually made by humans, in Illustrator or Corel
Draw or OO Drawing and can give very compact resizable files, which will be
in those products' native formats, or .wmf or .emf or perhaps one of the
postscript variants.

SnagIt gives you a raster file. Almost certainly it will be a hard-edged
sort of graphic, and so unsuitable for jpg which is a lossy format: it
sacrifices information to get a compact file*. It works wonderfully well but
only with continuous-tone images, like photos, for which it was designed. So
you want a lossless raster format. The old .bmp is such; it doesn't try to
compress and so it doesn't lose any information. It's just a bit map, as the
name implies. Pixel after pixel after pixel.... Then there are .gif, which
has a restricted palette but might do, and .png, which is usually the best
for this sort of thing. These two formats compress statistically and don't
sacrifice any information.

If you save a raster graphic in, say, .wmf, all you're getting is a whole
lot of tiny vectors, each of which looks just like a pixel.

>The size of the PDF is less important than image clarity.

Still, the above might shed some light.

Also note the point made on this list that PDF will try to compress, say,
.bmp images. BUT it might try to make them into .jpg images and the answer
is to fossick around in the Acrobat options to make sure it doesn't. This
may indeed be part of the answer you're looking for.

You say

> I then add graphical elements (numbers) and flatten the file before
importing it into MS-Word (as BMP
currently).

This may be the other part of the answer. You're capturing a screenshot
image of fairly crappy resolution and then adding the numbers. How?
PhotoShop maybe? So the numbers will be added as glyphs from a font, which
are vectors. PhotoShop can manage such vectors, but when you flatten the
image, they get rendered as pixels at whatever resolution you're using.
Let's say that's the same as the screenshot's original resolution; it will
be somewhat jaggified and nowhere near the clarity of the surrounding text.
Maybe you need to experiment with resizing your image to double (or more),
and try and get each pixel in the original shot to be a 2x2 (or more)
"super-pixel", while the numbers render at your doubled resolution.

I'm afraid this is getting somewhat too involved for a discussion list, but
you could experiment. And try all the tools you can, even vector ones.

>Since my original enquiry here, however, I'm told that MS-Word will
always lose image information. You can't control the output with MS-Word
in the same way you can, for example, with a proper DTP app.

Sure, a proper DTP app will be better to work with but this particular
calumny on Word is not true. Unless you do funny things like resize
inappropriately. For example, you might see Moiré effects if you resize an
image to 250 dpi and print it on a 300 dpi printer.

(* Yes, I know there's a lossless jpg now, but unless you know what you're
doing, just avoid jpg for hard-edged images. Also, Acrobat may see the jpg
and decide that it can further compress it. I don't know. One day I'll try
it.)



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