Image issues when converting PDF from PMS to CMYK using PDF-X3 preset

[prepressd85591261]

Hello,

I work for a printer who provides clients an Adobe preset to use when exporting print files. I've attached the .txt file of the summary. Sometimes our clients combine RGB, CMYK, and PMS colors & images in their documents. When they use our presets it converts RGB to CMYK, but not PMS. We support using PMS colors, but occasionally have to convert files to CMYK when printing offset. Sometimes everything converts fine, other times errors arise (white boxes around in place of cut out color images). The issues can be prevented if we have access to the working files, but that is not often the case. Our clients don't always know what method we are printing their work, and telling them to prepare the files 2 different ways is not an option. Today I exported a client's file using both the High Quality and Press presets, and everything on the resulting pdfs converted to CMYK correctly. Obviously that conflicts with the preset my work has been promoting for years. They had their reasons to decide on that preset initally, before I joined the company. I am not authorized tell a client to use different settings. My boss wants to know what the issue is with our preset. I don't know the answer. I'd appreciate advice on the matter. 

[Brad @ Roaring Mouse]

First of all, there should be no reason to be using a profile that creates Acrobat 4 (PDF 1.3) files this day and age, unless your company is using ancient RIPs. This old standard flattens the objects, which is undesireable. This bakes in flattening artifacts, like the stitching seams you speak of ("edges"). These show up because of the downsampling... Even at 300 ppi, each flattened object "block" will have a slightly fuzzy transparent edge of 1 pixel, which can allow the background to show through. Your RIPs will probably not show this at high resolution, but viewing the PDF can show these edges.

The recommended these days is PDF/X-4:2008 for any modern RIP. Even the two profiles you used (High Quality and Press presets) you mention are PDF 1.4, which does not flatten, as the RIP will take care of that.

"When they use our presets it converts RGB to CMYK, but not PMS"

Yup, this is correct. Despite what many think, the Convert to Destination does NOT convert PMS colours, only RGB. In order to convert PMS to CMYK, this has to be set in Ink Manager in the InDesign document prior to exporting. It can also be configured in the PDF in Acrobat. However, if you are wanting to control the conversion of a PMS colour accurately for your press, this is a job for your RIP workflow, so leaving these as spot in the PDF is preferable.

[prepressd85591261]

Thank you for your feedback. When I said "When they use our presets it converts RGB to CMYK, but not PMS" I should have made it more clear that this is not something we want to change. We do prefer to leave the PMS as spot for color accuracy. I have been frustrated with our profile for a while and suspected we needed to update it. I will suggest that now that I have confirmation. 

[rob day]

In highly automated printflows I still see printers requesting flattened PDFs—usually PDF/X-1a. Last I checked Vista Print, which might one of the largest printers in the world, requests PDF/X-1a.

PDF/X-4 is a very flexible standard, but if there isn’t a human on the output end checking the file, it can easily be broken. X4 would be better if you have customer service reps looking at the incoming files and outputting proofs, but with automated output and no reliable proofing (most online printers) an inexperienced or naive client might provide a PDF/X-4 that displays like this in InDesign:

But outputs like this because the InDesign blend space is set to RGB:

In this case PDF/X-1a’s flattening on export is a soft proofing advantage:

[prepressd85591261]

Ahh okay. Thanks for that information. We do send proofs, except for those that opt out. My employer wants to move towards automated proofing, and we are experimenting with an software to streamline that process. I can't find any PDF type requirements for the software in their Q&A. Not all of our clients use the preset we provide them or use Adobe programs to build their files. We've had several clients question the way images look (seeing image 'seams' etc.) when using our preset. Our digital pressman occasionally has to change settings for images/text not outputting correctly, mostly due to transparencies. I'm not sure if switching to PDF/X-4:2008 would help with that but I certainly hope we can figure something out. I did run a test export through the working files I mentioned in my question and customized the PDF/X-4:2008 preset to convert RGB as our preset does. I still have to review my findings with my boss, but I know they are hesitant to make any durastic changes.

[rob day]

I think the reasoning behind PDF/X-1a in a fully automated printflow, is it at least forces the client to view/soft proof the flattened transparency in the Output Intent destination CMYK space, hopefully before the file is sent. The default PDF/X-3 preset allows profiled RGB objects, but your preset is converting to CMYK, so I don’t think it is significantly different than the default PDF/X-1a standard, which doesn’t allow transparency or RGB color.

[rob day]

Hi @prepressd85591261 , Also, it’s the Swatch Spot Color Type that prevents the conversion to CMYK—all of the PDF/X presets keep Spot colors on a separate plate.

Your clients could choose a Pantone color from one of the Bridge libraries, which are defined as Process CMYK colors, or change the Solid Ink swatch Color Type to Process—in that case there would be a color managed conversion from Process Lab to your preset’s GRACoL CMYK Destination.

[prepressd85591261]

Thank you for your feedback.