The Ghent PDF Workgroup is an international organization which attempts to set best practices for different market segments in print production.
I believe though a committee process they attempt to establish the standards. But that doesn't mean that if they establish such a standard ("either a trim box or art box, but only one") that a file won't print in normal circumstances unless a RIP was set up to enforce such a standard.
Right. I just wonder why InDesign doesn't adhere to it -- especially as
Dov Isaacs is a party to both the GWG and Adobe, if I'm not mistaken.
If we're lucky, Dov might reply here. Keep in mind this is the end of Thanksgiving weekend in the US, and he might not have seen it.
You have not indicated what version of InDesign you used, but my tests using the latest versions of InDesign (versions 8 and above) do not yield the results you are getting.
Our assumption is that you export PDF from InDesign using the [PDF/X-4:2008] joboptions preset, possibly modified to use the output intent profile associated with your document's CMYK color space. I have attached a simple InDesign document as well as the resultant PDF file exported using that set of joboptions. Subjecting that PDF file to the Acrobat 11.0.9 Preflight Profile Sheetfed Offset (CMYK)(GWG2012), there were no errors reported. A warning was provided associated with my use of the US Web Coated (SWOP v2) profile instead of one of the Ghent Workgroup's recommended profiles, but there were no errors. And the PDF file contains no Artbox.
It is unclear why you are getting an artbox in your resultant PDF file. What version of InDesign are you using? Are you placing EPS files or PDF files (and from what program were they generated)? What PDF export joboptions are you using? Provide us with some additional information (including sample files) and we can try to track down the anomaly for you.
Although Adobe is a member of the Ghent Workgroup, Adobe absolutely does not recommend use of the GWG standards, including the most recent 2012 versions of those standards, as best PDF print publishing workflow practice!
Why? Very simple! The Ghent Workgroup 2012 standards, although finally allowing for live transparency in the PDF file, don't support use of color managed RGB or LAB imagery, whether raster image, vector, or text. (There are other “issues” in terms of unrealistic limitations, such as minimal image resolutions, but those could be the subject of other discussions.)
The reality of this is that the vast majority of raster imagery is RGB digital with ICC color profiles (there are obviously no CMYK-native cameras and scanners). Much creative content originally designed for web/screen display in Illustrator or Photoshop is created in RGB whether old time printers like it or not. Snicker if you wish, but the reality is that significant content placed into InDesign documents has origins in RGB applications (such as Microsoft Word, Excel, and PowerPoint as well as web browsers). Given that the content creators or even content aggregators typically have no idea what the final CMYK printing conditions will be (including whether offset, toner-based digital, inkjet, etc.), it is totally unrealistic to continue to support workflows that require early binding of content to a particular CMYK color space. This early binding is exactly what the current GWG standards require. PDF files created to GWG standards are highly device-dependent.
The current thinking of a majority of the Ghent Workgroup members is that at least RGB vector and text is somehow “unsafe” and therefore should be banned in the PDF file. However, this doesn't prevent users from using RGB vector and text content and doing poor CMYK conversions either prior to placement into InDesign or as part of such an placement operation! We believe that this “blame the designer, we only want CMYK as handed down by Moses at Mt. Sinai” attitude hurts not only the designers and print customers, but also the print service providers who are perceived to be offering anything but service. While it is true that there are industry wide issues associated with use of color and color management, legislating color space at the PDF level as opposed to providing reasonable educational material for use of RGB content and proper integration into a PDF publishing workflow is highly counterproductive.
Adobe's recommendations are based on our professional experience as a provider of graphic arts applications as well as direct PDF RIP/printer technology (Adobe PDF Print Engine) and that of many of our customers throughout the world. We recommend that you are much better off using the [PDF/X-4:2008] joboptions preset provided by InDesign with any adaptations strictly in the areas of output intent profile specification and possibly raster image downsampling and compression parameters. (The raster image downsampling and compression parameters “as is” are pretty much optimal for the vast majority of printing situations!) Adobe also views PDF/X-1a and PDF/X-3 as legacy standards that are best avoided in modern PDF publishing workflows.
If at some point, the Ghent Workgroup's standards reflect best practice 21st century PDF publishing workflows, Adobe will gladly officially endorse such standards. In the meantime, as members of the Ghent Workgroup, Adobe continues to work to try to convince other Ghent Workgroup members to move forward with less retrograde standards.
Thank you very much for the comprehensive answer.
I've been simply using the Press Quality joboption. 90% of what I do is black and white, so there are no colour issues anyway - the results are fine, and the printers here seem happy.
When exporting from CS6 (ME) with Press Quality, and preflighting with the GWG2012 profile, that's when the error about Trimbox & Artbox appears.
I just tried with the PDX/X-4:2012 joboption, and indeed the error is no longer there. I will be looking into switching to that.
The point about the GWG being a bit behind is taken -- I guess all committees have to struggle with that.
So my next question would be: Which Acrobat XI preflight profile is best for final checking of an InDesign PDF (usually a full length, b/w book) intended for sheetfed offset?
For a long time I was using Acrobat 7 and I would use Sheetfed Offset. Then, when we finally moved on the Acro XI, for some reason that profile is very slow. So I have gotten into the habit of using the one just below it -- the Sheetfed Offset GWG2012 profile, which for some reason is much quicker.
Our books are made very carefully InDesign, so this preflight is just used as an extra safety line.
So I'm wondering which Acrobat preflight profile you would recommend.
If in fact you need to use any of the GWG preflight profiles, then it is necessary to use the PDF/X-4 joboption in InDesign for PDF export since the GWG standards are a subset of PDF/X-4. However, since the GWG 2012 profiles expect all content in CMYK, you would need to modify the PDF/X-4 joboptions to specify that all color is to be converted to the output intent profile color space. (Yuck!)
In general, if you are creating PDF from InDesign destined for printing and don't need to concern yourself with the Ghent Workgroup standards, I would strongly recommend that you simply export the PDF using the PDF/X-4 joboptions with only the minimal changes necessary for your needs. For example, if you are printing very high quality offset with very detailed photographic imagery, the downsampling settings (300dpi for images over 450dpi) as-is may be too low although for the vast majority of printing, both offset and digital, they are quite fine as-is.
Preflight is really a separate issue. It really depends upon what you think might be wrong or go wrong. The actual structure of PDF files exported directly from InDesign (and not mucked with by other workflow programs) is very high quality. We don't normally hear of any problems. On the other hand, you may be looking for “issues” not with the PDF structure itself, but with the contents of the PDF file - basically what you did in InDesign. InDesign's internal preflight capability will find many of the design issues prior to creating PDF which is exactly what you want and need to do since InDesign preflight will point you to the “offending” graphic elements while in InDesign!
However, as an example of what you might want to preflight for in Acrobat, you mention that much of your work is black and white only. In that case, to make sure that your content didn't accidentally contain color, you can run the Single Fixup in Acrobat Preflight entitled Document generates more than 1 plate under the Document category. That effectively provides a programmatic method of the equivalent of paging through your entire document with the Output Preview - Separations panel opened with the Process Cyan, Process Magenta, and Process Yellow boxes checked and looking for anything other than a blank page! Note however, that InDesign's own preflight has a rule Cyan, Magenta, or Yellow Plates Not Allowed combined with the Spot Color Setup rule set to 0 colors which accomplishes the same test as you create your InDesign document!
My bottom line is that if you are well-disciplined in creating your InDesign document, if you have prudent InDesign preflight rules in effect appropriate for the document type you are creating, and if you use a reliable PDF export joboption such as PDF/X-4, running Acrobat preflight profiles may in fact be a waste of time and even counterproductive. On the other hand, if you are acquiring content from others who you don't particularly trust, then some individual preflight checks may be appropriate. However, I do not recommend any of the profiles under the Prepress category since they are all based on either the current retrograde GWG standards or even earlier versions of same and can actually degrade your output!
Thanks again for your information-replete answer.
Well, I've taken the plunge and used PDF/X-4:2008 for a couple of books now, so hopefully that will be okay. These are straighforward black and white productions, so I'm not really concerned.
I do use InDesign's Preflight, although I've never considered it a replacement for Acrobat's Preflight checks. So it was interesting to read your endorsement of it to that effect.
However, I do indeed always page through each book with the K plate off in Acrobat just in case. And the reason is that the Single Fixup "Doc generates more that 1 plate" (and it's equivalents in earlier versions) always generates a false positive for me. Indeed, I just tried it again with the latest book, exported from ID CS6 with the PDF/X-4:2008 joboption, and, as usual, I get a false error claiming that the doc uses more than one plate. I would be happy to send you the PDF if you're interested.