Can spot colours be proofed?

Since many printed matter contains spot colours such as Pantone or HKS, the question often arises whether these colours can be proofed at all. The answer is “no”. Only an approximate simulation of these colors is possible.
The reason: Each special ink is a specially mixed, “real” ink and therefore cannot be mixed from the 4 printing inks (cyan, magenta, yellow and black).

Today, modern proofing machines have up to 12 different printing colours and, in addition to the classic primary colours, also have, for example, orange and green and violet as real colour pigments in the machine. Proof printers such as the Epson SureColor P9000V are therefore capable of displaying significantly larger color spaces than, for example, ISOCoatedV2. The spot color simulation in these devices is therefore sometimes very good when controlled via a Contone driver, which can access the entire color space of the proof printer. Epson himself points out, for example, that “98% of all Pantone colors” can be covered. This may be doubted, but a number of over 90% of all Pantone colors is realistic from our point of view.

In the past, Pantone and HKS colors were simply converted by the proofing systems to CMYK and then simulated in the standard color space, i.e. mostly ISOCoatedV2. The representation of the colors here is mostly completely insufficient. For the reproduction of Pantone and HKS colours in a proof it is therefore immensely important to have a modern proof printer with many colours and a high colour gamut and a modern proofing software which is also able to precisely control the printed gamut.

Differences in the quality of the simulation of spot colors can quickly be seen in the different printing systems: If the proofing service provider prints with an older 6-color or 8-color system (Cyan, Light Cyan, Magenta, Light Magenta, Yellow and Black or Light Black), spot colors are simulated worse than, for example, with a modern 11-color system with Cyan, Light Cyan, Orange, Yellow, Magenta, Light Magenta, Photo Black, Matte Black, Light Black, Light light Black and Green.

The higher simulation quality of the spot colors is generated by the fact that orange, for example, already exists as a separate color and does not have to be mixed from magenta and yellow before the spot color simulation.

Of course, it must be said that there are limits, especially in the area of metallic or fluorescent colours; these colours are currently not reproducible in proofing.

The spot-colour simulation of gradations is also critical

In most proofing systems, only the 100% values of a Pantone or HKS color are underlaid. If, for example, a font logo with 100% color application of a Pantone color is to be simulated, this is precise and is well represented in most proofing systems.

However, it becomes more difficult if the logo contains not only 100% areas but also a 30% Pantone colour area, since this is not defined in the proofing system, but is simulated by the proofing system. In some cases, considerable deviations from e.g. HKS colour fans can be observed.

It becomes even more difficult if, for example, a grayscale TIFF lies on a 100% HKS area and overprints. For the graphic professional it is immediately comprehensible that the HKS surface simply has to become correspondingly darker at this point due to an overprinting 30% black. However, the proofing software must recognize this effect correctly, calculate it correctly and then simulate it correctly with the 11 colors available from the proof printer. It is easy to understand that countless errors can occur. And the supreme discipline: 7-colour Pantone files with lots of overlaying and overprinting Pantone colours or HKS colours with overprinting CMYK elements can at best be calculated even by the most modern proofing systems, but can by no means be colour-accurately simulated.

The bad news is that a proof with spot colors is therefore never as color-binding according to the current state of the art and varies more depending on the proofing system.

But the good news is that spot colors, especially solid colors, can now be simulated well by modern proofing systems. A modern proofing system therefore also offers the possibility of getting a realistic impression of spot color prints at a fraction of the cost of a test print on a offset press.

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Embed fonts, convert them into paths or rasterize them?

To ensure secure data exchange between customers and proofing service providers, fonts must be embedded, converted into paths or rasterized. This ensures that it is and remains exactly the same font and exactly the same style.

How do I do that?

  • With InDesign and QuarkXPress, you select the PDF/X-3 standard when exporting data.
  • For Illustrator and Freehand, select the font and select “Convert font to paths” from the menu.
  • In Photoshop, select the text layer, right-click on it and select “Rasterize Text”.

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What is the UGRA-Fogra Media Wedge 3.0 used for?

Every print shop in Germany adheres to a predefined standard, the process standard offset printing. This standard defines target and tolerance values for printed products. In order to prove that your proof delivered to the print shop meets these standards or is within the tolerances, the media wedge is measured and the values analysed in case of doubt – i.e. in case of a streak. If these measured values are correct, the print shop is obliged to adhere to and achieve these values.

Practice generally shows the following: If you want to have a 4-page image brochure proofed and printed, it is usually sufficient to have a single media wedge printed under the 4 pages. If the media wedge is also provided with a test report, the colour accuracy for the print shop is directly confirmed as a guideline.
However, if you want to be on the safe side, have a separate media wedge (including test report) printed under each of the 4 pages of your brochure.

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How color-accurate are proofs?

A proof is prepared according to the currently valid ISO standard 12647-7 and is legally binding with a UGRA-Fogra media wedge and measurement report.

How does this check work?

If you need a proof with UGRA/Fogra Media Wedge CMYK V3.0, there are two ways to add the test report to your data.

  1. With proofing devices in which a measuring device is integrated, the media wedge with 3×24 standardised colour fields is printed directly under the proof data. This media wedge is driven directly in the proofing device to a kind of “hair dryer” in the measuring device and dried there. After a few minutes of drying, the media wedge continues and is measured directly in the proofer. This takes a few minutes. The measured values determined in this way are returned to the proof server and evaluated there. If the color values are correct and within the tolerances of the strict ISO standard, a test report of the measurement is then printed directly under the media wedge, which guarantees you color accuracy in accordance with the process standard offset printing.
  2. For proofing devices without integrated measuring device, only the standardized media wedge is printed under the proof data. A check takes place subsequently and outside the proof printer. The media wedge is then measured with an external measuring device and the target and tolerance values are output to a label printer. This label is then stuck directly under the media wedge.

What is the advantage of automated creation and checking of the media wedge directly in the proofing device?

  • Measurement is automated directly after proof printing, measurement errors due to manual operating errors are excluded. Since the test report is not subsequently attached, as is often still the case, manipulation is impossible.

Further information on the test report, the media wedge and on the work and responsibility of UGRA/Fogra can be found at www.ugra.ch and www.fogra.org.

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