error in flattening transparancy and spotcolors

[TonvdM]

We have several InDesign-jobs where images with a dropshadow are positioned over a separate box with a spotcolor-fill. The jobs are exported to PDF version 1.3. The images in the resulting PDF show a white box around the transparent element. I've tried several settings in the flattener panel, but without result. In Acrobat the white boxes are invisible when overprintpreview (option-shift-cmnd-Y) is activated, but on film the problem is still present.

I realise that the best way to make PDF is through PostScript and Distiller but our customers don't all use this method.

The solution for full-color jobs is changing all spotcolors to CMYK, but this is no option for spotcolor-jobs. How can I create PDF 1.3 with dropshadow and spotcolors?

In advance: thanks for your help.

 

[jimoblak]

I realise that the best way to make PDF is through PostScript and Distiller but our customers don't all use this method.

This may not really be the best method. Direct PDF export from ID is recommended by Adobe.

There are some unknowns to your post: version of ID, what kind of image with a drop shadow is positioned over a separate box (CMYK/spot/black/semi-transparent?), what type of RIP that you are using, why you are restricted to PDF 1.3...

As a quick fix, you might try experimenting with the different blending modes that are offered with shadows.

- - picklefish - -
Why is everyone in this forum responding to me as picklefish?

 

[TonvdM]

Some extra information:
* version InDesign: CS (3.01)
- it happens with CMYK and grayscale images from Photoshop with clipping path (saved as .psd of .eps) and CMYK and grayscale illustrations from Illustrator (saved as .ai)
* we are using a Agfa PDF-RIP Series 2 version 2.0 (but even before RIPping the problem is visible)
* PDF 1.3 because of cPDF in our country and because of the limitations of our advertorial system
* I found out that making PostScript en PDF with Distiller also is no solution
* I have tried most options for blending (from Normal and Multiply, saturation etc) but without any result. Besides it all works well as long as all colors are CMYK. As soon as the background is a spotcolor the white boxes appear.

 

[camspr]

What happens if you print this PDF as separations (from Acrobat 6) to for example a Laserprinter?

Most likely the seps will be exactly what they should be (at least they are in my tests). Looks to me like that Agfa PDF-RIP has got a problem here. Some how it can't handle the overprint that is used in the PDF file correctly. I do not think it is a problem with the flattening or the PDF file for that matter. Proper support of overprint at the RIP is essential for flattening to work.

Using the separation preview in either ID or Acrobat 6 (Professional) will show you what the separation should be (given a RIP that thus what Adobe is expecting it to do).

 

[MarcusStringer]

I had the same problem.

I found that going to PDF-1.5 (Acrobat 6) fixed the problem. Also make sure the RIP is PS level 3. The Agfa RIP I was sending to was not and that also caused problems.

If you must use PDF 1.3 then create the drop shadow in Illustrator.
Also be Careful mixing PMS with CMYK I don't think PDF-1.3 (Acrobat 4) supports Device-n colour spaces which is what it needs for PMS Colours.

I also found the suppling pre-seperated PDF's will ensure almost trouble free work. compared to combined two colour PDF (v4) which Agfa Rips don't seem to like.


Marcus

http://www.midlandtypesetters.com.au