PDF 2.0 and PDF/X-6 – The New PDF Standards

PDF 2.0 Standard: The new standard for PDF filesFor 20 years now, PDF/X standards have been available for the printing industry and have enjoyed great popularity. Now, with the introduction of PDF 2.0 in 2017, another milestone in PDF standards has been introduced, having been developed by numerous PDF experts over many years. And just recently, the ISO published a new revision of PDF 2.0. Soon, the new printing standard PDF/X-6 will also take shape, which contains several innovations in detail compared to PDF/X-3 published in 2002 and PDF/X-4 adopted in 2008. The old PDF standards will retain their validity, but the new ones will certainly find their way successively into the software and processes of the printing industry.

New in PDF 2.0:

  • PDF/A-4 according to ISO 19905-4:2020 – PDFs for archiving
    • The creation of PDF/X-4 data for long-term archiving is getting leaner, as some specifications have been dropped. Digital signatures are facilitated, form fields are now supported.
  • PDF/X-6 according to ISO 15930-9:2020 – PDFs for professional printing
    • The most important innovation is the page-based output intent: A brochure whose cover is printed on coated paper and the inner part on uncoated paper can now be exported as one PDF file with two output conditions: PSOCoatedV3 and PSOUncoatedV3, mixed according to pages. Previously, a file could only contain one output profile. Also new is the depth compensation and the embedding of spectral data for spot colours according to CxF-4. This makes it possible to transfer spot colours with a spectral definition and not just write a LAB or CMYK value into the PDF. Also new is the support of multicolour profiles, i.e. ICC profiles with more than four colour channels. The new PDF/X-6 standard is very similar to PDF/X-4 in many aspects.
  • PDF/VT-3 according to ISO 16612-3:2020 – PDF exchange format for transactional printing
    • The term transactional printing may not be familiar to many media designers. It covers the printing and processing of data for the creation and printing of invoices or account statements, for example. Transactional printing refers to all processes, i.e. from the export of data from an SAP system etc. to the printing, processing and dispatch by post or email to the return of the dispatch into SAP. The new VT-3 PDF standard specifies the parameters for this variable, transactional printing.
  • PDF/R-1 according to ISO 23504-1:2020 for scanning in PDF data
    • A brand new standard is the R-1 PDF standard, the “raster” standard. Developed by the Twain people, it is only relevant for the creation of raster image documents, i.e. scans of pages or images.

The most important innovations for us in the printing sector with the introduction of the PDF 2.0 standard are, of course, the PDF/X innovations with the leap from PDF/X-4 to PDF/X-6, which is being developed on the basis of PDF 2.0.

  • Page-related output conditions: The best examples of applications in these areas are certainly brochures with covers: If, for example, the cover was previously printed in 4/4 colour on glossy picture print and the inner section on uncoated paper, then this could only be realised via two PDFs, one for the cover, one for the inner section. Now a brochure PDF can carry both output conditions, even a colourful cover and a black and white inner section can be combined into one PDF.
    But in application we would certainly like to use this for typesetting work at any time. For us in proofing, this probably has little practical effect, because coated and uncoated paper would also be printed on different proofing papers, so we would have to split the one file into two proofing jobs. Of course, we could also go the comfortable way and proof the uncoated paper on a proof paper for coated paper, but this would not be very comfortable for the viewer in terms of the effect. Sampling a natural paper interior from a natural paper proof onto the production paper is much more coherent and visually better. In laser print-based environments, however, individual paper trays and processing methods of a printer could be assigned to profiles, for example, so that these features could be better used here in daily work. Up to now, this could be done via a job ticket that was created and processed with the PDF file, but now it could be done directly in a document.
  • Spectral data according to CxF-4: Spot colours can now be defined spectrally. The new CxF-4 format, which has also become an ISO standard, is used for this. This is certainly important in two cases: On the one hand, spectral data can contribute to a more precise colour definition of spot colours than pure LAB, RGB or CMYK values are capable of. Especially on modern seven- and multi-colour printing systems with their enormous colour gamut, almost the entire PANTONE colour palette can be reproduced. Especially here, the use of spectral spot colour definitions would certainly prove its worth.
    For us, this is not really an issue in proofing at the moment, as we will probably see little spectral data in customer data. However, in our special applications such as the HLC Colour Atlas or the production of calibration targets for customers, we could well imagine the more frequent use of spectral data. In the new generation of ICC profiles, multicolour ICC profiles can also be used, and the colour sequence in the printing units and the overprinting behaviour can now be better defined. Here, too, we are curious to see how the latest developments will find their way into our work.

DeviceLink PDF Colour Conversions for Ads

We have recently started offering DeviceLink colour conversions via DeviceLinks made by ColorLogic from numerous RGB and CMYK standards into other CMYK standards from offset and gravure printing.

DeviceLink PDF Colour Conversion

Optimised colour conversion between different printing standards

The colour conversion profiles preserve the separation structure, limit the total colour application for the selected printing standard and maintain the purity of the primary and secondary colours. They ensure smooth transitions in gradients and enable correct conversion of PDF and PDF/X data. Separation-preserving conversion ensures that pure grey tones are not built up into four colours and that duplex tones (black+primary colour) and triplex tones (black+secondary colour) remain pure, while still being colour-metrically transformed in the best possible way. In addition, the colour impression of the source colour space is optimally preserved in the target colour space by taking into account both paper colouration and dot gain.

Limitation of Total Allocation of Colour (TAC)

For current printing standards of ISO, Fogra, ECI, Ifra, Gravure (PSR), Gracol, Swop, SNAP, these profiles ensure a targeted limitation of the maximum ink application without completely new separation. This reliably prevents problems with set-off and improves the drying behaviour. These profiles are suitable if the data is generally already in the desired colour space, but individual images or objects have too much ink application.

You can order the Devicelink PDF colour conversions for advertisements here

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What data should I give for proofing?

A proof is suitable for two types of color control: firstly, during the creation or retouching phase, e.g. to reconcile a color retouched image with the original, and secondly to check the final data directly before printing.

For control proofs during the data creation of a project, the data format usually does not matter. Whether PDF, JPEG, TIFF; EPS, PS or even PSD… Many proofing companies accept a variety of data formats. For a correct evaluation of the result, however, it is important to proof in the color space in which the print product is also created later. Data for a letterhead should therefore be proofed in ISOUncoated or PSOUncoated, while products printed on image printing paper should be proofed in ISOCoatedV2. For yellowish paper, newsprint or gravure printing, there are many other profiles for which a proof can be produced. You can find a good overview of the current proof profiles here. It is also important that the proof format and the final print format do not differ too much. Only in this way is a correct check possible.

When the brochure has been laid out or the catalogue production has been completed, a proof should be prepared again for the final check by the customer. This proof is then created with exactly the same data that is also sent to the print shop. This is usually a PDF X/3:2002 file, as this is the preferred data format for printers. If the pages are delivered to the printer with bleed marks and bleed, then the proofs should actually be created in exactly the same way. The finished proofs can then first be used as approval for the customer, and secondly for checking the OK sheet in the print shop. This ensures that no unpleasant surprises wait for the customer (what does the colour look like????) or the printer (why does the customer make a complaint?????) after printing and bookbinding.

PDF/X4 – The future of PDF/X?

The PDF/X4 standard, a new PDF specification for PDF export, has already been available for several years. But what are the advantages of PDF/X4?

Users from the print sector have known the ISO PDF-X standards for many years. If the name PDF stands for “Portable Document Format”, i.e. the portable and thus transferable document, PDF “X” is a version specialized for “eXchange”, i.e. the exchange of PDF files. In concrete terms, this means that many of the functions that a PDF file can potentially display (form fields, calculations, 3D elements, films, etc.) but which cannot be controlled in print are prohibited in PDF/X in order to ensure secure data exchange. (more…)

Why is the embedding of RGB profiles so important?

A few days ago we received a call from a customer in the field of design, who sent open Adobe InDesign data in ISOCoatedV2 300% with contained RGB images to the production company for a complex CD production on the advice of the producing company (“The printing company still has a prepress stage, which can then prepare your data optimally…”). The result of the finished printed CD booklets and inlays did not correspond at all to the calibrated monitor image of our customer, the client was also unhappy and requested the print data about the production company from the print shop responsible for the print to troubleshoot. Data in the “US Web Coated” color space with 350% ink coverage came back from the printer. For troubleshooting, the customer then had a proof of his data created by us, but had chosen the settings “Convert to target profile (retain values)” as usual when writing the proof PDF; we thus received completely CMYK data, of which we produced a proof according to ISOCoatedV2 300%, which completely met our customer’s expectations. So it seems that the designer created the data correctly and printed the print shop incorrectly.

On closer inspection, our error analysis revealed two serious weaknesses:

  • On the one hand, the obviously wrong profile conversion of the print shop with InDesign CS2 to “US Web Coated”, a completely outdated profile never used in Europe, which was delivered with early Creative Suite versions and was probably never adapted due to a lack of competence on the part of the print shop.
  • On the other hand, the open InDesign file of our customer, which he had sent to the production company, contained RGB images without a profile (DeviceRGB), which cannot be safely interpreted.

In this case, a complaint of the designer to the printing company will of course be difficult, as on the one hand, non-profiled RGB data were sent to the production company, and on the other hand, no print PDF generated by the data creator in the correct output color space ISOCoatedV2 300% was supplied.

If this had been done, one could at least have argued that the expected color of the production print would have been comprehensively known. Thus, one can only refer to the fact that the printer would have had to ask the designer for RGB data without an embedded color profile, and should not have assigned the data somehow to a profile “blindly”. The fact that the print shop with its crude US Web Coated workflow certainly did not create a correct print file, but a wrong one for the output, can indeed be stated, but the print shop can always talk its way out to “systems with in-house standard”.

How do we deal with RGB data at Proof.de?

If we receive a PDF file that contains RGB images, the next step is to check if the file is a valid PDF/X-3 or PDF/X-4. If this is the case, we check whether all input RGB profiles are correctly marked with color space (sRGB / AdobeRGB / ECI-RGB-V2 etc.) and rendering intent, then we check whether the correct output color space was used as output intent and whether also contained CMYK data have the correct input profiles. If yes, then we proof the file with the settings: “Consider all input and output color spaces”.

In this case, the file is reproduced 100% exactly as our customer created and defined the color profiles. If he has made a mistake and e.g. marked an image with a wrong RGB profile, this will also be “incorrectly proofed” exactly as correctly.

If RGB data should not contain a profile, e.g. if they are created in Device RGB, we generate a “data incorrect” e-mail in which we explain our procedure as follows:

“Dear customer, the data check has shown that RGB elements are contained in your data. RGB elements can only be safely interpreted in the proof if they are marked with a color profile and a rendering intent. This is the case, for example, with correct PDF/X-3 and PDF/X-4 data. The correct output intent must also be specified.

At least one of these criteria does not seem to be the case for your file. The safest way would be to convert the contained RGB data to CMYK. This has the advantage that you have control over the conversion and can view the CMYK result again in Acrobat before uploading the file again for proofing. We can then reliably use your CMYK values for the proof. To do this, call up the current order in your customer account, delete the incorrect data and upload the corrected data.

If, for example, the RGB element should only be a small image that is not relevant for the overall impression of the proof, or if you do not have another file available for the proof, then of course we can also use your RGB data for the proof. If available, we use your RGB source profiles and rendering intents, otherwise we use the sRGB standard and the rendering intent “relatively colorimetric with depth compensation”, which in most cases will lead to correct proof results. If you would like us to proof the supplied RGB data in this way, please let us know. Please do not hesitate to contact us if you have any questions. Best regards, your proofing team”.

In our case, the CD production case would also not have occurred in the proof, as we reject RGB data not provided with an ICC profile with the error message mentioned above, and do not convert them, as we cannot predict precisely how our customer would have liked the data to be converted.

We are aware that our approach is not 100% the ultimate best approach in all cases, but to the best of our knowledge and belief it is best in line with market practice and the expectations of our customers.

However, we are also happy to accept your individual requirements and circumstances. Give us a call or send us an email and describe your processing requirements.

Colour Management Consulting and Expertise

Colourmanagement Consulting
Colourmanagement Consulting

By the way: We are happy to put our knowledge and data competence at your service: If you also have a problem, a question about print data, data preparation, or – as in the above example – a misprint has already occurred and you need external expertise and assistance for the complaint: Give us a call. We will be happy to advise you and help you where we can help. We will charge you for our advice and analysis at an hourly rate of EUR 90,- plus VAT, and you will be billed for 15 minutes each. An initial consultation and assessment is of course free of charge.

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