Easy conversion of Pantone – HKS – CMYK – RGB with Adobe Photoshop

Farbbücher Auswahl in Adobe Photoshop CC: HKS, Pantone, CMYK und vieles mehr

More often the question arises as to what kind of Pantone colour corresponds to the HKS 43 K. Or what CMYK value? And what kind of web color in RGB?

If you own Adobe Photoshop, you can do these conversions directly there. In Photoshop CC all well-known color books are stored with values.

Let’s assume we are looking for the Pantone equivalent and the matching CMYK color of HKS 43 K.

1: Open the color palette in Adobe Photoshop and select HKS K as the book and then the color HKS 43 K. All well-known colour books are directly stored in Photoshop.

Farbauswahl von HKS 43 K im Buch HKS K in Adobe Photoshop CCThe color corresponds to a Lab value of 26/29/-79 and a CMYK value is already stored here. Simply select the book HKS K Process: Continue reading

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:
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Why monitor and paper don’t get along when it comes to color.

Colour is colour, you’d think. That’s right. But have you ever tried to explain the colour of your new car or your new red wallet to a friend on the phone? You will notice that human color recognition and the reproduction of the same in another medium is very difficult.

The same applies to computers – better: monitors, and printers – i.e.: laser printers, inkjet printers or newspaper printing or offset brochure printing.

Why is the red on a monitor different from exactly the same red printed on paper? It’s simple: put the paper in front of the monitor. The two shades of red are exactly the same. Like this. And now you’re completely darkening the room. What do you see? The red on the monitor is still red. And exactly the same red on paper? This is black now. Why is that? Very simple:

Translated with www.DeepL.com/Translator

A monitor adds light, i.e. spectral components, to the existing ambient light. If you see red on a monitor, it is because the monitor actively emits red light.

And now the paper: When do you see red on paper? Exactly when white light falls on the paper, for example through a window or a lamp. And when do you see the color red on paper?

When white light falls on the paper and the paper extracts the non-red spectral components from the white light and reflects the red light. That’s when you see the color red.

One colour, two completely different ways of production. And this is exactly where the color calibration and the proof start. The strategy? Fairs. And this under fixed conditions and not with the human eye, but with “incorruptible” technology.

Put simply, a monitor calibration device can measure your monitor and see exactly “how much” color your monitor can display, and “how wrong” your monitor can display color. And if your computer knows that, it can correct the monitor.

Another measuring device can emit neutral white light onto a paper and measure the reflected color. Depending on the printing process and paper, the ink looks completely different, but the meter again sees “how much” ink the print can represent and “how wrong” the print represents ink. And if your computer knows this, it can correct it. And:

If the computer knows the color representation of the monitor and printer, it can correct and adjust the representation so that both correspond to the same color. Of course, this only works if the color and brightness of the light that illuminates the paper is also known and standardized.

And how does the proof work? Very simple:
If a computer also knows that the final printed product is to be printed in offset on an image printing paper, and it knows the colour representation of this printing process, then it can simulate this on a monitor and on an inkjet printer.

On the monitor, this color-accurate representation is a so-called “soft proof”, the color-accurate preview of the subsequent print on the inkjet printer is called “Proof” or “Contract Proof”.

This inkjet printing must be very precise and meet the highest demands in gamut and color simulation. And since the image processing technology, color matching calculation and measuring technology behind it is not very cheap, proofs are still mostly “expensive” inkjet prints. Due to new printing systems and inexpensive and better measuring technology, however, prices have also fallen significantly here in recent years.

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What’s a proof for? The most important reasons for proofing!

  1. A proof is reassuring:
    The proof shows the colour result of the subsequent printing.
    The customer knows exactly the later result from the proof and is reassured.
    The printer knows that the customer knows the proof and is also reassured.
  2. A proof is fast:
    Ordered today, delivered tomorrow: Modern proofing service providers work quickly and produce hardly any loss of time in the design and printing process
  3. A proof is precise:
    All professional service providers nowadays work with proof printers that are recalibrated at short intervals. A media wedge with test report also provides clear metrological proof that the proof is correct and within the limits of the standard deviations.
  4. A proof is cheap:
    In the past, repro studios often charged almost 30 euros for an A4 proof. Nowadays, it only costs a fraction. Proofing costs are of little importance in the production process.
  5. A proof also shows the colors that the monitor does not show:
    In most agencies, hardware-calibrated proof monitors are in short supply. And TFTs or old tubes show colors, but unfortunately some. A proof also depicts colors that standard monitors cannot display, but which can be printed.
  6. A proof simulates newspaper as well as coated paper.
    If the same advertisement is to appear in the glossy brochure for the trade fair stand, in the trade fair news and in the special supplement in the local daily newspaper for the trade fair, then the three different colour results can be excellently simulated and presented in proofs in advance. And who knows: Perhaps the customer will then have the house brochure printed on picture printing instead of on uncoated paper due to the proof, or will choose a different motif for the newspaper ad. The proof shows it.
  7. A proof can do CMYK and more!
    Modern proofing systems can reproduce up to 98% of all Pantone colours and HKS colours in the proof.  This means that not only four-color, but also five, six and multicolor files can be proofed. Today, proofing is often done twice: once in CMYK plus corporate color in Pantone and once in CMYK and corporate color in CMYK. The client and agency can then decide whether the colour result is worth the extra charge for the fifth colour in the print.
  8. A proof is made of paper.
    Just like the product he’s simulating. A proof can be placed next to the print and compared under Normal. And to check it out, you can carry both to daylight, look at them in the candlelight and much more. A soft proof cannot do all this.

This is the first incomplete list. You know of other good reasons? We look forward to any comments and would be happy to add further points.

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Embed profiles for proofing? Yes or No?

The question often arises whether color profiles should be embedded in the PDF files for proofing.

To answer the question, you have to get some answers: The proof should simulate the subsequent offset printing. For offset printing, with few exceptions, the imagesetters have been configured so that a 70% black in the file is displayed as 70% black on the printing plate, no matter what profile was specified in the file. It didn’t matter whether it was coated paper or uncoated paper: 70% in the file corresponded to 70% on the plate, the choice of the paper printed on resulted in the colour representation.

The proof has also adapted to this: Most proofing service providers ignore embedded profiles, as long as the data is in CMYK and do the same as their print colleagues. Even with grayscale, the profiles are usually ignored and the grayscale is simply assigned to the CMYK black channel. Thus all CMYK and grayscale data are simply interpreted as if they had been created in the output color space. If “ISOCoated V2” is proofed, all images are treated as such, and if “PSOUncoated” is proofed, then the CMYK images are created in this color space.

This is excellent for the majority of files to be proofed. Only RGB colors contained in the data are problematic.
Since the RGB color space is considerably larger than most CMYK color spaces, it must be clear from which color space to convert to CMYK according to which criteria. Most proofing service providers specify a color space from which they convert by default if no RGB color space is defined. This can lead to difficulties: For example, many proof studios choose AdobeRGB as color space because it is large and optimized for offset printing; however, most images from digital cameras come from sRGB and these color spaces differ considerably. Therefore, it is important that the RGB color space and the rendering intend is embedded for a proof, otherwise the proofing software normally selects a color space for conversion to the CMYK color space to be proofed; and this color space is possibly not the one in which the data has be created.

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