Visible trapping on digital proof PDF files

[Justin de Kruyf]

I'm looking for a way to provide a proof in PDF format with visible trapping.

We work in InDesign CS6 and I recently learned that by sending a file from InDesign to out Xerox C75 with the "In-RIP Separations" output setting we're able to accurately simulate trapping and discover trapping issues with a digital proof that would otherwise occasionally make it onto our plates. Now I'd like to figure out a way to apply trapping to our PDF proofs.

I tried outputting to postscript with In-RIP Separations and our trapping preset, and then creating a PDF from that postscript file in Distiller. This actually worked to a degree - there's visible trapping in some places. However it also created a lot of terrible artifacts around some of the type and didn't trap some places where it should have. (See attached screenshot - there's visible trapping around the text and the edge of the blue graphic element, but the text has been ruined)

Is anyone familiar with a process to output a PDF with trapping? Ideally we'd like to be able to do this right from InDesign but if there's a solution that would take a PDF exported from InDesign and apply trapping from there, that'd be fine too.

 

[DCurry]

The problem with your workflow is that when you print to a PostScript file, you flatten transparency at the same time. That makes it harder to trap because you have many little atomic regions and sometimes, elements like text that should stay crisp vectors get flattened into rasters, so the parts of your text that stayed vector should trap fine, but the flattened parts might not trap well.

You could get a standalone PDF trap solution (there are several out there - I'm sure someone will suggest a few to look at.) Then, you would ideally export to unflattened PDF, trap the PDF, then feed that to your RIP and proofer, provided they can handle live transparency.

(Personally, I feel that if the RIP that generates the plate data isn't the same RIP that generates the proof, then the proof is no good.)

 

[Justin de Kruyf]

You could get a standalone PDF trap solution (there are several out there - I'm sure someone will suggest a few to look at.) Then, you would ideally export to unflattened PDF, trap the PDF, then feed that to your RIP and proofer, provided they can handle live transparency.

Digging through a thread on trapping software from elsewhere in the forum I'll see if I can get my hands on any of the following for testing:

I-Trap from trapping.org
Heidelberg's PDF Toolbox
Esko Deskpack

(Personally, I feel that if the RIP that generates the plate data isn't the same RIP that generates the proof, then the proof is no good.)

Probably true. We're running a fairly dated Harlequin RIP and I don't have a deep enough understanding of how this system works yet.

I'm a fairly new hire and the company I work for has been doing things the same way for a long time, but they've been running into unexpected trapping issues that cost a lot of money. If I can find the right solution then I might eventually be able to get it implemented, but I'm learning as I go.

 

[akalaray]

Heidelberg - Trap Editor - Plug in to Acrobat - excellent application. We also have in rip trapping for trapping in line. Use trap editor for complex/pms/double hits.