Based on the fact that your printed copy looks correct, I still think it
might be a display issue.  A quick and easy way to check it would be to
create a test document containing multiple instances of the same image,
each at a different size (either by specifying a scaling factor, or by
specifying hard dimensional constraints (like pt or cm)).  I'd bet (if I
were a gambling man) that all of the printed results are going to look
good, while your on-screen representations are going to be a crap shoot.

Is the purpose of your project to create PDFs that are going to be
primarily viewed on-screen, or on hard copy?  And if possible, could you
send me a copy of the offending PDF, and the image itself? (In a separate
e-mail directly to my address; you'll probably get scolded if you post
potentially large attachments to the group.)


                    "Stephan Wiesner"                                           
                    <[EMAIL PROTECTED]       To:     <[EMAIL PROTECTED]>        
          >               cc:                                
                                             Subject:     RE: Quality of 
                    11/15/2002 12:36                                            
                    Please respond to                                           

Hi Jef and thanks for the fast reply.
The printout looks fine. It is printed with 100%, though, so that was to
be expected.

I use the current Acrobat Reader to view my files and I have commercial
Documents, with graphics that look great no matter how large I scale, so
it can not really be the viewer?


> -----Original Message-----
> Sent: Freitag, 15. November 2002 18:19
> Subject: Re: Quality of Grafics
> Stephan-
> Are you noticing degraded image quality in a printed version
> of the PDF, or only in an on-screen display?  If it's in the
> on-screen display, I would attribute the degradation to the
> way the PDF Viewer handles scaling of images.  Rather than
> using a nice, blurred scaling algorithm, I believe the PDF
> Viewer uses a quick and dirty single-sample scaling
> algorithm, which can lead to distortion of the images,
> especially when viewed at odd factoring sizes like 66% or 75%.
> If it's in a printed PDF, then I have no explanation,
> although I'd like to see an example.  I've implemented a
> system using FOP, which embeds hi resolution JPEGS into a
> PDF, and the printed output looks good, while the on-screen
> output can sometimes be a little grainy.  It's not terribly
> noticeable on my images, since they're photographs, and don't
> generally have hard edges, which tend to show scaling
> shortcuts more than soft gradients.
> Hope that helps.
> -Jeff

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