Hi dbky1,
Image file formats can be mysterious things. There are so many of
them and each one has advantages and disadvantages. As you've come to
realize, working with image files between programs can be terribly
frustrating.
Part of the problem lies in the different way that Illustrator and
Print Shop work with graphics files. Illustrator works with vectors,
which are mathematical descriptions of the image, while Print Shop and
Photoshop work with bitmaps, which actually describe each pixel of the
image. Getting the two to cooperate can be a bit challenging.
Your problem could be coming from a couple of places. First, the file
format you choose is going to make a big difference. I'll give a
quick run-down of the various formats in general use:
JPG: By far the most common format, at least on the web. It produces
very small files by using a lot of compression. However, this is
"lossy" compression, so image quality gets lost with this format.
This makes it particularly unsuitable for resizing images because the
size change combined with the lossy format can do some very funny
things. It allows 24-bit color, but does not allow transparency.
GIF: Also a lossy compression format, though not as lossy as JPG. The
images are restricted to 8 bit color which makes the format unsuitable
for many uses. Files can have a transparent color which is useful for
web design.
BMP: This is a pure bitmap file. The file describes each pixel one at
a time without compression. The disadvantage is the very large file
size, but the image quality will never degrade.
TIFF: Perhaps the most common for high quality images and for graphics
work, this format allows for some compression but can be set to
loss-less compression sot that the image quality does not degrade.
This format is often used for master copies of images because of this
ability, but the file sizes are quite large. This format allows for
24-bit color.
PNG: One of the newest formats, this provides loss-less compression
but better file sizes than TIFF. It also supports 48-bit color and
transparency. Most newer applications will be able to read this
format, but it is not as widely compatible as TIFF.
There is an excellent discussion of the GIF format here:
http://www.dsdesign.com/articles/gif.htm
A comparison of JPG vs GIF can be found here:
http://www.wfu.edu/~matthews/misc/jpg_vs_gif/JpgVsGif.html
And a nice file format comparison chart can be found here:
http://psego.tripod.com/format_comparison.htm
So part of your problem may be coming from using the wrong file
format. If you're importing in to Illustrator and resizing this then
a lossy format is not going to be a good choice for you. It will tend
to make the picture jagged. TIFF or PNG are probably your best
choices.
The other part of the problem may be coming from the image resizing
itself. Illustrator often doesn't do a very good job of resizing
images that it imports. There's probably a technical reason for this,
but I don't know it. However, there's a good work around. I use
Photoshop not Paint Shop, but I imagine the controls for this are
fairly similar. What you need to do is resize the image in Paint Shop
and then import the resized image in to Illustrator. PS does a much
better job of resizing than Illustrator does. Unfortunately I'm not
familiar with Paint Shop, but in Photoshop (and it must be similar in
Paint Shop) you need to open the image, then select Image -> Image
Size. This brings up the image resize window. Make sure you keep
"constrain proportions" checked off. This means that the resized
width and height will always be proportional to the original in the
same ratio. This keeps the image from getting squished. Pick the
size you need the final image to be and click OK. Make sure that you
save this resized image with a DIFFERENT file name otherwise you will
have lost your original which has more information in it. Resizing
back up from the new smaller file will not yield the same quality as
the original.
If you're resizing the original image to make it larger then you are
almost certain to run in to problems with quality no matter what you
do. By blowing the image up you are asking to get more information
out of the file than is actually there. Unless you spend a lot of
time retouching the expanded image it is certain to look a bit funny.
As far as books go on the subject, there aren't any books that I'm
aware of that specifically deal with this question without going in to
way more detail than you would ever want. But if you head down to
your local book store and browse through files about
Illustrator/Photoshop you should be able to find one with a good
discussion of these issues.
I hope this helps you out. Let me know if you need more information.
- Hibiscus
Search Strategy: gif vs. jpg, graphics file format comparison, image
file formats |
Request for Answer Clarification by
dbky1-ga
on
20 Jan 2003 15:18 PST
I still need more information, maybe I did not clearly state my
question properly. I am sending graphics images to someone who is
putting those graphics into an AI file, This file is being constructed
for the purpose of being sent to a printer for comercial printing. In
the file you can see a clear indication that the text is fully
vectored, ie, it apears as complex mapping. The graphics however,do
not appear with the same sort of mapping on the screen, in fact they
appear wrinkled and unclear with no mapping at all. The graphics are
in eps format when I send them to her. My question is, is this the
expected manner in which the gr should be apperaing in her AI file?
Also, will this be suitable to meet the requirements presented my her
comercial printer to whom she is submiting this file, if not, in which
specific format should I be sending these files to her, if not eps,
and what should the appear like on her screen?
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Clarification of Answer by
hibiscus-ga
on
20 Jan 2003 15:59 PST
Ah, I see now what you meant. Sorry I didn't answer that before.
The files you are sending are EPS files which is a vector format, but
if the EPS file was created from a bitmap image then you won't have
the mapping that a pure vector file would have. Mostly this means
that you can't resize the image without losing quality. There's no
way around that if your original is a bitmap. However, by sending a
high enough quality image to be incorporated in the AI file you
shouldn't run in to problem. TIFF or PNG may be the better way to go.
But realize also that what you see on screen is not necessarily what
you'll see on paper because the screen resolution differs quite a bit
from the print resolution. There is no reason, however, that a file
which is of the right size and of a high enough resolution (presumably
very high if it's being professionally printed) should print badly,
even if it looks a bit odd on-screen. Screen resolution is less than
100 dpi, so high quality images can lose something in the translation
to screen. The test would be to print the AI file on a reasonably
good quality printer to make sure that the final output isn't becoming
mangled somehow. In the end though, if your original image is a
bitmap, when you put it in to AI it will not look as clean as AI's
vector graphics, especially if you are zooming in.
Let me know if you still need more information.
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Request for Answer Clarification by
dbky1-ga
on
20 Jan 2003 18:03 PST
Hibiscus,
|
Request for Answer Clarification by
dbky1-ga
on
20 Jan 2003 19:06 PST
Hibiscus,
Thank you for you patience and sharing of your knowledge of graphics.
We are just beginning to get into graphics and design in a small way
and sometimes feel very overwhelmed with all of this. If we could ask
just two more questions if you don't mind. One, are the files
converted in Streamline considered "Vectored" graphics? and is there a
easy way to determine the PPI of a file?
Thanks
DBKY1
|
Clarification of Answer by
hibiscus-ga
on
20 Jan 2003 21:34 PST
Hi again,
The answer to the Streamline question is yes, Streamline converts
images to vector files suitable for use in Illustrator. However, it
can be difficult to get a decent quality image out of it, particularly
if there are a lot of color variations in the original. Fiddling with
the settings might improve this for you, but it depends quite a bit on
the file. However, if you manage to produce a file that still looks
the way you want it then it would be perfect for use in Illustrator.
As for determining the resolution of the file, this is probably
viewable inside Print Shop. Again, since I'm more familiar with
Photoshop I can't tell you the exact steps required to find the
information out, but in Photoshop you could just click Image -> Image
Size which is the same window you use for resizing. In the Document
Size section it tells you the resolution of the image. Or, a little
shortcut is that you can hold down the Alt button and then click and
hold the mouse button over the Document info bar at the bottom left.
In Photoshop Elements the image resize is under Image -> Resize. I
imagine that if you look through the help in Print Shop you should be
able to find something about image resizing. I looked around for a
while to find a quick little utility that could tell you the image
resolution in ppi but without any luck.
If you know the width and height of the image though, as well as the
actual pixel dimensions, then it's pretty easy to calculate this for
yourself. For instance, I have an image that is 444x150 pixels, and
6.167x2.083 inches. 444/6.167 = 72. 150/2.083 = 72. So the
resolution is 72 dpi.
Good luck getting all this figured out! If you find that Print Shop
just isn't cutting it for you, you can get an evaluation copy of
Photoshop Elements (which has most of the Photoshop features that the
non-professional user will need) from Adobe here:
http://www.adobe.com/products/tryadobe/main.jhtml#product=40
- Hibiscus
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