[PDF] Images appearing blurred in PDF
Gauri Kulkarni
display
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Hi Gauri,
First of all, gifs are invariably low res (72dpi) files and are only really
suitable for viewing on the internet, for example.
Secondly, what you are seeing in your pdf is a preview of the image rather
than the image file itself.
I suggest you look at the original picture files in photoshop if possible,
and have a look at the quality/resolution etc.
With regards to distiller settings you might want to look at the resolution
the images are being downsized to (150pdi is the minimum you need), and
check what option of pdf is being selected - if you need to print good
quality files then you need press-optimised settings.
Hope this helps,
Chris (Express and Star).
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Michael Jahn
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On 10/1/03 6:54 AM, "Gauri Kulkarni" <ga...@versant.com> wrote:
> I am using Acrobat 4.0 and am converting Word documents (manuals) to =
> PDF.
> The documents have large amount of images (dialog boxes), captured and =
> inserted as GIF's.
> My problem starts once the conversion is done to pdf:
> All the images appear blurred and the text on them is non readable.
>
> Is there something I can do to increase the image quality in the final =
> output?
> Can the distiller settings be changed for better o/p?
> Is there any workaround for this problem?
> I would appreciate if any help is given.
I see no reason that you can't use GIF files that are probably screen
captures - if they open and are legible enough in a web browser, they will
work fine. They are the resolution they are - up-sampling or making the
scale factor something different in Photoshop will not make anything any
sharper.
You probably have downsampling turned on in Distiller. Turn it off.
I think this is how you get to Job options in Acrobat 4 (I am using 6)
Acrobat Distiller > Edit (or General?) > Job Options
Go to the compression Tab (or Images?)
Just turn it Subsampling or (Downsampling ?) to None or off
Hope this helps.
Dan-Ari Feinberg listreader
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I was not following this thread carefully, so please excuse me if someone
has already mentioned this:
If you have screen shots as GIF files, then the culprit in fuzzy images is
not the resolution but the compression. JPEG compression will cause your
screen shots to be fuzzy, probably no matter how high a quality (and low a
compression) you set it for.
My bet is that you have Compression set to Automatic or JPEG. Set the
compression to ZIP.
ZIP is a lossless compression that is well suited for screen
shots. Lossless means that when Acrobat decompresses the image to display
it, the data will be the exact image that you fed into Distiller. JPEG is
lossy compression, which means that what you get after decompressing is not
what you started with. The idea is that your eye won't notice the
difference, but with screen shots or any hard-edged line art, you will
notice, as you have.
There is something called 4-bit ZIP. (At least I think there was in
Distiller 4.) This drops the least significant 4 bits of each byte,
keeping only the 4 most significant bits. In essence, it rounds off the
color values. This is a lossy process. Then, the data is zipped, and this
part of the process is lossless. What is being lost is that color values
are getting rounded off, but individual pixels are not being combined with
other pixels, thus 4 bit zip will not cause blurriness, but it might cause
color banding if you have lots of smooth shading.
I am reaching into my memory banks, but I seem to remember that GIF images
fool Distiller. Distiller has compression settings for Color Images and
Monochrome images. (I don't remember if Distiller 4 uses those same
names.) Your GIF files make Acrobat Distiller think that they are color
images, and it will use the JPEG compression that you surely have set as
the compression for Color Images.
If some of those GIF files are true contone image files and you want them
JPEG compressed, you may have some luck changing the screen shots into
another file format that Distiller will recognize as not contone and will
not use the Color Images compression setting.
Contone - continuous tone. As in, a photograph, where colors span a
continuous range of tones. This is different from an indexed image like
your screen shot, where there are certain set color tones (red or black or
white, etc.) but not every color in between.
Regards,
Dan-Ari
Walter S. Hemingway
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I have been creating images and pages in Illustrator and then converting
to PDFs. My graphics have no anti-aliasing. What is going. What do I
need to set to keep the edges from looking blocky?
Peace, Love & Nappiness
WaltSH
(803)748-8594
wa...@medianetwork.ws
"(After choosing a song), what you take is the song itself," he said.
"The recording is simply that day, that time and what the person
(performing) was feeling. You take the best out of it, but you have to
recreate it yourself."
Leon Redbone
-----Original Message-----
From: owne...@lists.pdfzone.com [mailto:owne...@lists.pdfzone.com]
On Behalf Of Dan-Ari Feinberg listreader
Sent: Thursday, October 02, 2003 4:23 PM
To: p...@lists.pdfzone.com
Subject: [PDF] Images appearing blurred in PDF
Scott, Kenneth A
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I have seen this several times. Your file is probably still intact if you
print it (the vector information will not be so jaggy). However it looks
blocky on screen. There is a preference setting in Acrobat that will
"smooth" or anti alias these. With a pdf open in acrobat, go to EDIT,
PREFERENCES, SMOOTHING. You should see an option for smooth text, smooth
line art, smooth images. (depending on version of Acrobat). For some
reason these don't seem to be ON by default?
Ken
Walter S. Hemingway
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Thanx you guys. I probably should have known this.
Michael Jahn
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On 10/3/03 3:21 PM, "Peace, Love & Nappiness wrote:
> I have been creating images and pages in Illustrator and then converting
> to PDFs. My graphics have no anti-aliasing. What is going. What do I
> need to set to keep the edges from looking blocky?
Converting to PDF ?
1 - how are you converting ?
2. - do you realize that you can turn text smoothing on ? I think you are
having a display engine issue - simply turn on smoothing in your Acrobat
preferences (you didn't say what platform or version, so I can't help
explain where to find this setting.
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