Layout in RGB, print in CMYK. Problems?

 

Especially in larger companies today the layout in RGB is the rule rather than the exception. The advantages are obvious:

  • The layout takes place in a large, almost media-neutral color space
  • All Photoshop filters are available without restrictions
  • The process of color space conversion to CMYK is shifted to the production process as late as possible

In practice, however, there are two potential problems in particular.

Problem 1: CMYK conversion in the last step.
The catalogue is designed in InDesign, all data is perfectly matched, the last step before printing and proofing is the export to a printable PDF in CMYK. Usually this is done via a preset in InDesign, which defines the exact specifications for the color space conversion. In practice, however, this color space transfer can hardly be monitored. The problem: Even if you check the color values in Acrobat in the exported PDF file, for example, Acrobat does not really display the colors it contains. Acrobat brav would show you CMYK values even if the RGB images are still wrongly contained. However, other CMYK values can occur during printing when the data is processed again. Lately it looked like this:

  • Customers supposedly send CMYK data to the proof.
  • 1. data delivery: Most pictures are still in RGB. The customer did not notice this when looking through Acrobat.
  • 2nd Data delivery: Data in CMYK, printable and proofable, therefore a proof is made. However, the data was converted using an incorrect profile, so all images were yellowish. In this case, the wrong color space conversion was only noticed in the proof.
  • 3. data delivery correct. Data in the proof is also correct.

Another problem: finishing in the print shop

  • A print shop receives Darten from Corel Draw, which were laid out in RGB and converted to CMYK during export.
  • Original images from the photographer in ECI-RGB-V2
  • Corel of the designer who takes the images from the photographer set to sRGB
    The export is to a CMYK PDF. The designer doesn’t know if his Corel vector areas in RGB black were calculated differently than the RGB images embedded by the photographer, which hide their black via layer mask on these vector areas.
  • Feedback from the print shop after data receipt: The black has too much ink application. The customer and the designer are completely insecure. Of course, nobody really knows how Corel handles RGB data – possibly profiled or unprofiled – when exporting to CMYK.

Granted: Such problems would never have arisen with a CMYK workflow. CMYK is the lowest common denominator between agency, photographer and printer. Nevertheless, I favour the RGB workflow for the future. Correctly applied and set up, it holds the chance of significantly better printing results, since the conversion to CMYK can take place as late as possible. But this also means that color management know-how must be available “as late as possible” in the process steps. And it is precisely here that many print shops simply have to fit. This is because most – including larger printing companies – proceed according to the principle:

“Somebody came along and installed the CTP. He was gone after three days, and it’s worked ever since. We put data in at the front, and printing plates come out the back. What’s in between? I don’t know. Why?”

This is what happened recently to a customer. For the printing of a brochure with photographs that run out into deep black and fall off the edges, the print shop received feedback that the images should be placed so that the black consists of 40/0/0/100.

Granted: That a deep black can have a CYAN admixture was certainly taught 30 years ago in vocational school. And 40/0/0/100 is also black. However, asking a photographer to align his RGB images to this black level is not really appropriate. But that’s exactly how it happened with a customer. Conclusion: RGB is good, but has not yet reached all printers. However, the printers who can look beyond their own horizons have certainly already dealt with the subject.

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