Stephan-
Glad I could help (even if it was in a passive way)
Just a few parting thoughts on the matter, although it sounds like you've
got a pretty good idea of what's going on already. Before you go on,
though, I must apologize for the use of U.S. units (inches, dots per inch,
etc.) I'm just used to dealing with said units, and things actually come
out to nicer, rounder numbers when using inches. So...
You're right that scaling the image down will both reduce the size of your
PDF, and the quality of the image. There are a few things you can do to
find a happy medium between PDF size and image quality. The most obvious
is to make sure you're using images of an appropriate resolution. If
you're using a digital camera, to take 1600x1200 images, and the images get
printed in a 4inch by 3 inch rectangle on your PDF, you're looking at a
printed resolution of 400 DPI (Dots (or pixels, if you prefer) Per Inch.)
My system is meant to allow people to choose ad templates, fill them with
assets (copy, headlines, and photos) from a database, and create a
print-ready PDF, meaning that said PDF could be taken to a commercial
printer for a run of 50,000 copies, or submitted to a magazine or other
print publication for publishing. I use 300 DPI as a minimum for my
output, and the results are of the same quality as most glossy magazine
advertisements. If that kind of quality is not necessary, you may want to
try printing a PDF with the image printed at 200 DPI (this would be a
800x600 pixel image, provided the print dimensions are still 4 inches by 3
inches, as in my previous example.) This halves your resolution, but
reduces your image size (for an uncompressed image) to 1/4 it's original
size.
A secondary way to reduce the size of your PDF, while (mostly) preserving
image quality is to use JPEG images as an input, and to play with the
quality setting of the JPEG. It's my understanding that when FOP puts
images into a PDF, it internally converts them to a JPEG, UNLESS the input
image is already a JPEG, in which case it simply embeds the image in the
PDF. Basically, this means that by using JPEG-formatted images as your
input, you have direct control over the number of bytes your image content
takes up in the resulting PDF.
Depending on your requirements, you may be able to significantly reduce the
size of your PDFs by using these 2 methods in some sort of preprocessing
step between pulling the image from the camera, and generating the actual
PDF.
Sorry about the huge reply, especially if it's information you already
know. I didn't realize it was going to be this big, but perhaps it'll help
some poor soul searching the archive in the future.
-Jeff
"Stephan Wiesner"
<[EMAIL PROTECTED] To: <[EMAIL PROTECTED]>
iesner.de> cc:
Subject: RE: Quality of
Grafics
11/15/2002 01:27
PM
Please respond to
fop-user
Hi Jeff,
Okay, I did prepare a document to send to you and, of course. I can get
fine quality if I use very large pictures. I made them with my digital
camera at 1600 resolution and formerly cut it to 25% size. This looked
still very good on the screen, but not in the PDF. When I don't reduce
the size, the quality is fine. This is, in my oppinion, because now the
picture is at 100% when I set the Acrobat to 400%, which I don't do. The
drawback, of course, is that the PDF gets real huge. I suppose that is a
price I will have to pay, though and I can live with that.
So, you helped me without really doing anything :-)
Stephan
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]
> Sent: Freitag, 15. November 2002 18:46
> To: [EMAIL PROTECTED]
> Subject: RE: Quality of Grafics
>
>
>
> Stephan-
>
> 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.)
>
> -Jeff
>
>
