Tiled /Sliced images in a PDF

Gregg

Well-known member
Recently, I was attempting to edit an image from a PDF. I was unsuccessful because the image was broken up into several slices. Having never seen this before I did some testing (placing flattened TIFs and PSDs with transparent backgrounds in ID and then PDFing from there). Seems transparent images all come out sliced up. Is that true or am I overlooking something? Is there any way around that? What issues, aside from non-editable imagery does this pose?

Thanks in advance.
 

Dov Isaacs

Well-known member
Re: Tiled /Sliced images in a PDF

You did not indicate what program you used for layout or how your created the PDF file from that original document and program, but what you are seeing is only one of the ramifications of creating a PDF file that does +not+ maintain live transparency. Flattening transparency going into PDF most often requires dumbing content that is non-opaque or that intersects objects that are not opaque into multiple opaque objects. The resultant PDF file is difficult to touch up because of such object decomposition and/or in some cases, objects being changed to less-editable forms (such as text to vectors or rasters and vectors to rasters). You also could end up with stitching artifacts.

This is exactly the reason for moving to a PDF print publishing workflow in which content is maintained at the highest level of abstraction all the way to the RIP process. PDF/X-4 - in final stages of ISO publication - promises to provide a prepress standard supporting such workflows.

- Dov
 

leonardr

Well-known member
Re: Tiled /Sliced images in a PDF

There are MANY reasons why an image can come out "tiled or sliced" when
using it as an asset that is used to produce a PDF.

Certainly, transparency flattening is one reason - since if you have
transparent objects on top of the image, there is a good chance that it
will be "cut up".

In addition, some applications use a memory-saving technique called
'banding' the breaks the image up into strips/bands. Not only do
applications do this, but many printer drivers do as well - it's one
reason Adobe recommends that IF YOU MUST print to Postscript, use the
AdobePDF Printer.

And there are a variety of other reasons. It's up to your authoring
environment and the settings and workflow that you choose.

Now - will it have any impact on the final document? No, it shouldn't.
(other than hindering late stage editing).

Leonard
 

Gregg

Well-known member
Re: Tiled /Sliced images in a PDF

Thanks Dov and Leonard.

To be more specific. I was using InDesign CS2 as my layout app. I was ripping a postscript using the High Resolution setting for my tranny flattener and then creating a PDF using Distiller 7 (Press Quality setting).

Edited by: Gregg on Jan 3, 2008 2:07 PM
 

Dov Isaacs

Well-known member
Re: Tiled /Sliced images in a PDF


You've just provided yourself with the best reason in the world to create PDF from InDesign via *+export+* instead of creating PostScript and distilling. Use export joboptions that create PDF 1.4 or greater!

- Dov
 

UncleSam

Well-known member
Re: Tiled /Sliced images in a PDF

Yes, when you export your layout to Postscript or PDF 1.3 (Acrobat 4) or PDF X1A (=PDF 1.3), you are flattening your transparency effects and it will slice up your images in order to flatten those effects. If you export your PDF directly from InDesign or other Adobe software, you can chose PDF 1.4 or up (Acrobat 5 or up), that will let you to maintain all transparency live. Of course if your RIP is not up to date and can't support transparency, you will have a hard time to output your file correctly. If you use Quark, sorry, there is no way to keep transparency live in Quark, it must be flatten!

I'm suggesting our customer to send us PDF 1.4 or up to keep all transparency live in our shop and that way, we have more control how we want to output it!
 

leonardr

Well-known member
Re: Tiled /Sliced images in a PDF

Just to be pedantic, and to ensure that no false rumors are started...

Flattening transparency DOES NOT ALWAYS split up images!!

It's dependant on numerous factors including (but not limited to), what
type of object(s) are superimposed on the image, what blending mode(s)
are in use and what colorspace(s) are represented. Oh, and of course,
your flattener settings of 'vector vs. raster'.

Leonard
 

alang66

Member
Re: Tiled /Sliced images in a PDF

The issue is with the compression I think. JPEG compressed images come out sliced, regardless of whether they are transparent or not. I think you'll find that a JPEG2000 compressed PDF image does not split up into loads of pieces. I've not experimented with loads of tile sizes but I use 1000 pixels and that seems to work all the time.
 

Franknater

Well-known member
Re: Tiled /Sliced images in a PDF

We just got a pdf with the slices. I'm not sure how it was done, I know the problem exists in Illustrator if images are not embedded. Perhaps one is placed in InDesign?

Frank
 

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