Convert PANTONE colours optimally into CMYK. Practical aspects to the new old discussion.

A very frequent topic for us in the area of proofing is the optimal conversion of PANTONE colours in CMYK for classic, inexpensive four-colour printing. In the last few days, there has been a lively discussion on this topic in the Adobe Forum and in the colour management forum of hilfdirselbst.ch, which I would like to summarise briefly, as our customers often struggle with the same issues.

PANTONE and the PANTONE CMYK values from Bridge: The Problem

The central question is to which standard or colour profile a CMYK value of a PANTONE colour in Bridge actually refers. Specifically, a user asked for the conversion of PANTONE 116 C, a colour tone that is specified in the PANTONE Bridge fan in CMYK 0/14/100/0 (here you can see the original value in PANTONE). But if you now convert the underlying PANTONE Lab color value in InDesign or Photoshop into different CMYK profiles, you will get different, significantly different color values. “What does the PANTONE Bridge CMYK colour value refer to” was the original question of the discussion.

The starting point of the PANTONE Bridge fan

In the PANTONE Bridge Fan, “equivalents” of the PANTONE spot colours on a coated and an uncoated paper grade, separated with 4 Pantone scale colours, are visualised and the CMYK values are specified.

But one thing is clear: without precise information on the substrate, print density, inks used, etc., the information provided there has only limited validity. If, for example, one converts the LAB colour value of PANTONE 116 C into the SWOP Web coated commonly used in the USA, then one reaches a value of 20 in magenta instead of 14 as indicated in the PANTONE Bridge Fan.

Comparison of PANTONE LAB values with PANTONE Bridge CMYK values in PSOUncoatedV3 and PSOCoatedV3

If you compare the original PANTONE LAB values and the PANTONE Bridge CMYK values in European standards such as ISOCoatedV2 or PSOCoatedV3 for coated or PSOUncoated or PSOUncoatedV3 for uncoated paper, there are sometimes serious colour deviations. The PANTONE Cool Gray 2 is much too light in CMYK conversion, the PANTONE Cool Gray 11 is always much too dark. For the PANTONE 3278 C, the Bridge CMYK value for PSOCoatedV3 fits quite well, but the same comparison for Uncoated is noticeably worse. What is the reason for this?

Comparison of PANTONE C Solid Coated LAB values with PANTONE Bridge CMYK values in PSOCoatedV3 colour space
Comparison of PANTONE C Solid Coated LAB values with PANTONE Bridge CMYK values in PSOCoatedV3 colour space
Comparison of PANTONE U Solid Uncoated LAB values with PANTONE Bridge CMYK values in PSOUncoatedV3 colour space
Comparison of PANTONE U Solid Uncoated LAB values with PANTONE Bridge CMYK values in PSOUncoatedV3 colour space

The question was therefore specified once again:

  • How can PANTONE specify “official” CMYK values for a particular colour if it is not clear what paper white, print density, ink coverage, etc. the values refer to?
  • How does PANTONE arrive at the specified colour values?
  • Which ICC profiles are possibly the basis?
  • Are there errors if programs such as Photoshop or Affinity Publisher do not show the same values when converting a Pantone color as those specified by Pantone?

Thesis 1: Why should a spot colour manufacturer deliver perfect CMYK replacement values for his products? That would be detrimental to business.

One thing is clear: there are no system errors. PANTONE knows what they do. But it is surprising that the bridge values have apparently been fluctuating by several percentage points for many years. Perhaps one reason for this is that different base pigments have been used over the years and the values have therefore been adjusted. But it was not possible in any way to find out how the values are created, what profiles or logic could be behind the values. Some discussion participants thought of a deliberate system error: “Cui bono? Why should a spot colour manufacturer deliver perfect CMYK replacement values for his products? That would be detrimental to business.”

This is an exciting approach which, at second glance at the latest, does not lack a certain logic. If the head of the company has only seen bad CMYK conversions of his PANTONE spot colour for long enough, he will sigh and agree to any surcharge for a five-colour print, only to finally find his corporate colour correctly reproduced again.

But another thesis is also very plausible:

Thesis 2: The sales department defines the CMYK values

Let’s assume that a PANTONE “Green1” corresponds colorimetrically to a CMYK of 30/0/100/0. If two more saturated green tones (“Green2” and “Green3”) are displayed in the fan, which theoretically should be displayed with CMYK 35/0/110/0 and CMYK 40/0/120/0, what then?

To set all three green tones to CMYK 30/0/100/0, i.e. the next CMYK value that can be achieved absolutely colorimetrically? That would actually be the most obvious way, especially since it is very unlikely in practice that two adjacent PANTONE colours would ever be used in CMYK conversions. Because a company has either green1 or green2 as its corporate colour, but hardly both at the same time.

On the other hand, buyers of PANTONE Bridge fans would probably be very surprised if different PANTONE colours in the fan had the same CMYK value.

Therefore, a psychological-sales-department correction is obvious: In order to avoid identical CMYK values, we set the most saturated green tone to the not matching CMYK 30/0/100/0, and then the less saturated colors to 25/0/0/90/0 and 20/0/0/80/0, i.e. also not matching CMYK values. Now nothing fits anymore, but at least all colors have different CMYK values.

Practice shows: An adjusted conversion via ICC profiles often provides a better CMYK color value for the conversion of PANTONE colors like the CMYK value from the PANTONE Bridge.

We have converted the PANTONE colours used in the above mentioned graphics also via ICC profiles partly absolutely colorimetrically and relatively colorimetrically with depth compensation (marked with an “r” behind the CMYK colour value) into the two output colour spaces PSOCoatedV3 and PSOUncoatedV3 and have mapped the visually best match in each case.

In most cases, this conversion adapted to the output color space delivers the significantly better results. See for yourself:

We support you in determining the optimal CMYK conversions for your PANTONE house colours

If you need the best possible conversion of one or more PANTONE colours to CMYK, we will be happy to support you with our know-how and our measuring and proofing technology. We determine and compare different imaging variants of a PANTONE colour in CMYK and show you the best determined conversions in CMYK with metrological evaluations in Delta-E00.

How to match the production paper, proof standard and the proof precision of spot colours

Today a customer called who wanted to order a proof of several HKS N spot colours on an uncoated paper. “Which proof profile should I choose? And how exactly can you match my special colours in the proof? I probably have to proof several HKS N red tones in comparison. By the way, the printing is to be done on Fly Cream, a slightly yellowish paper.”

What is the paper white of the production paper?

First of all, I searched with the customer for the production paper in our paper white database. A quick look via full text search revealed that we have measured Fly Cream from Papier Union:

Fly Cream enthält gemäß unseren Messungen keine optischen Aufheller, also "keine OBA". Das LAB Papierweiss liegt bei allen drei Messungen bei rund  LAB 95 / 0,7 / 9,2
According to our measurements, Fly Cream does not contain any optical brighteners, i.e. “faint”. The LAB paper white in all three measurements is around LAB 95 / 0.7 / 9.2

With a B-value in LAB of 9.2, Fly Cream is really not just a little yellowish, as the customer said, but clearly yellowish, chamois, creamy … whatever you want to call it. So it was natural to check the proof profile “ISOUncoatedYellowish”, Fogra 30, to see to what extent the paper white could match.

What is the paper white of the possible proof standard?

Together with the customer we looked up our “paper white of proof profiles” table:

Das Papierweiss des Proofstandards Fogra30, ISOUncoatedYellowish
The paper white of the proof standard Fogra30, ISOUncoatedYellowish in LAB: 95.93 / -0.77 / 3.85

Contrary to the customer’s expectations, the paper white of ISOUncoatedYellowish is not even as yellowish as the paper white of the edition paper Fly cream, which is more yellowish by more than 5 steps on the B axis. So it was clear: PSOUncoated as a brighter-free uncoated paper proof standard is clearly too white, ISOUncoatedYellowish is much more suitable.

On what kind of proof paper will this proof standard be printed?

(more…)

PANTONE and HKS colour deviations in proofing updated

PANTONE and HKS color deviations in proofing. All PANTONE color systems and HKS and HKS 3000+ for proofing standards without optical brighteners and standards with optical brighteners have been updated in the past months.
PANTONE and HKS colour deviations in proofing. All PANTONE colour systems and HKS and HKS 3000+ for proofing standards without optical brighteners and standards with optical brighteners have been updated in the past months. https://shop.proof.de/info/spot-color-tables.html

Current proofing systems can reproduce spot colours such as HKS or Pantone very well. With the Fiery XF 6.5.2 proofing software and the Epson SureColor-P9000V Spectro proof printer, we have evaluated the colour deviation in Delta-E00 with which the various PANTONE and HKS colours can be proofed. On shop.proof.de, the tables are now available for all important PANTONE and HKS colour systems, sorted by colour fans.

A distinction is made between the proofing substrates that we use, since the surface texture and the paper white also have an influence on the representability of the colours. The colour deviations were calculated by the proofing software on the basis of the measured colour space of the proof.de proofing system. Deviations are therefore possible in practice. However, it turns out that almost all spot colours can be simulated quite well in the large colour space of our proofing devices. The smaller the ∆E00 value, the smaller the colour distance from the spot colour reference to the proofed colour. Higher ∆E00 values show which colours can be reproduced more poorly in the digital proof.
As a rough guide: From ∆E00 > 1 a colour difference is visible to the human eye, below it it can only be measured, but not seen.

Colour deviations from PANTONE EXTENDED GAMUT Coated in the proof in Delta-E (∆E)

Current proofing systems can reproduce spot colours like HKS or Pantone very well. Using the Fiery XF 6.3 proofing software and the Epson SC-P9000V proof printer, we evaluated with which colour deviation in Delta-E the PANTONE Extended Gamut Coated colours can be proofed.

The colour deviations were calculated by the proofing software on the basis of the measured colour space of the proofing system of proof.de. Therefore in practice there may be deviations. However, it has been shown that almost all PANTONE colours can be simulated quite well in the large colour space of the proofing device.

The smaller the ∆E value, the smaller the colour distance from the PANTONE reference to the proofed PANTONE colour. Higher ∆E values indicate which PANTONE colours can be reproduced in the proof with greater difficulty.

PANTONE
EXTENDED GAMUT Coated

Delta-E Colour Deviation
Proof

PANTONE
EXTENDED GAMUT Coated

Delta E
Colour Deviation Proof
PANTONE 100 XGC 0.24 ∆E PANTONE 355 XGC 0.84 ∆E
PANTONE 101 XGC 0.24 ∆E PANTONE 356 XGC 0.00 ∆E
PANTONE 102 XGC 0.49 ∆E PANTONE 357 XGC 0.64 ∆E
PANTONE 103 XGC 0.64 ∆E PANTONE 358 XGC 0.27 ∆E
PANTONE 104 XGC 0.93 ∆E PANTONE 359 XGC 0.27 ∆E
PANTONE 105 XGC 0.77 ∆E PANTONE 360 XGC 0.59 ∆E
PANTONE 106 XGC 0.24 ∆E PANTONE 361 XGC 0.65 ∆E
PANTONE 107 XGC 0.50 ∆E PANTONE 362 XGC 0.35 ∆E
PANTONE 108 XGC 0.25 ∆E PANTONE 363 XGC 0.38 ∆E
PANTONE 109 XGC 0.26 ∆E PANTONE 364 XGC 0.88 ∆E
PANTONE 110 XGC 0.57 ∆E PANTONE 365 XGC 0.26 ∆E
PANTONE 111 XGC 0.98 ∆E PANTONE 366 XGC 0.27 ∆E
PANTONE 112 XGC 0.36 ∆E PANTONE 367 XGC 0.55 ∆E
PANTONE 113 XGC 0.25 ∆E PANTONE 368 XGC 0.61 ∆E
PANTONE 114 XGC 0.50 ∆E PANTONE 369 XGC 1.04 ∆E
PANTONE 115 XGC 0.50 ∆E PANTONE 370 XGC 0.00 ∆E (more…)

How accurate can PANTONE colours be reproduced in proofing?

Pantone colours can be simulated very well today. T be able in advance to see how well your Pantone colour can be reproduced, we have published tables of all Pantone inks where the colour differences of the Pantone colours can be looked up already before proofing.

Colour variations of Pantone colours in Delta-E

Colour variations of Pantone metallic colours in Delta-E

We have now even photographed some pictures that visually show how appropriate proofs on the latest Pantone subjects.

PANTONE Solid Coated Fan colors vs. Digital Proof (more…)

Colour deviation of Pantone metallics and Pantone Premium Metallics colours in proofing in Delta-E (∆E)

Current proofing systems can print spot colours like Pantone or HKS very accurate. With Fiery XF 5.2 Proof software and the Epson 7900/9900 proof printers we evaluated, with which colour deviation PANTONE Metallics Coated and PANTONE Premium Metallics Coated colours can be reproduced in proofing.

The colour deviations were calculated based on the measured colour space of the proof system of Proof GmbH by the proofing software. Deviations should therefore be quite similar in practice. Almost all PANTONE colours can be simulated quite well in the wide colour gamut of the proofer.

The smaller the Delta-E value, the lower is the colour distance of the PANTONE reference to the proofed PANTONE colour. Higher Delta-E values ​​show, which PANTONE colours can’t be simulated accurately in the proof.

Please note: Since the proof devices does not have colours with metallic pigments, the metallic shine in the proof can not be reproduced. Only through the satin finish of our proofing paper a somewhat shiny effect is produced, which replaces partly the metallic luster of true PANTONE colours. Although the colour is well rendered, the metallic effect in the proof does not exist. The proof can therefore always be used only as a guide, but not as binding simulation of the final result.

PANTONE Metallics
Coated
Delta-E Deviation
Proof
PANTONE
Premium Metallics Coated
Delta E
Deviation
Proof
PANTONE 871 C 0,71 ∆E PANTONE 10101 C 1,49 ∆E
PANTONE 872 C 0,72 ∆E PANTONE 10102 C 1,77 ∆E
PANTONE 873 C 1,03 ∆E PANTONE 10103 C 1,00 ∆E
PANTONE 874 C 1,26 ∆E PANTONE 10104 C 1,42 ∆E
PANTONE 875 C 0,97 ∆E PANTONE 10105 C 1,42 ∆E
PANTONE 876 C 0,86 ∆E PANTONE Silver C 1,65 ∆E
PANTONE 877 C 1,37 ∆E PANTONE 10106 C 1,09 ∆E
PANTONE 8001 C 1,52 ∆E PANTONE 10107 C 0,97 ∆E (more…)

Colour differences of Pantone Solid Coated and Pantone Solid Uncoated colours in proofing in Delta-E (∆E)

Current proofing systems can print spot colours like Pantone or HKS very accurate. With Fiery XF 5.2 Proof software and the Epson 7900/9900 proof printers we evaluated, with which colour deviation PANTONE Solid Coated and PANTONE Solid Uncoated colours can be reproduced in proofing.

The colour deviations were calculated based on the measured colour space of the proof system of Proof GmbH by the proofing software. Deviations should therefore be quite similar in practice. Almost all PANTONE colours can be simulated quite well in the wide colour gamut of the proofer.

The smaller the Delta-E value, the lower is the colour distance of the PANTONE reference to the proofed PANTONE colour. Higher Delta-E values ​​show, which PANTONE colours can’t be simulated accurately in the proof.

Pantone Farbe
Solid Coated
Farbabweichung im Proof in
Delta-E (∆E)
  Pantone Farbe
Solid Uncoated
Farbabweichung im Proof in
Delta-E (∆E)
PANTONE 100 C 0.89 ∆E PANTONE 100 U 1.69 ∆E
PANTONE 101 C 0.60 ∆E PANTONE 101 U 1.62 ∆E
PANTONE 102 C 1.23 ∆E PANTONE 102 U 1.40 ∆E
PANTONE 103 C 0.72 ∆E PANTONE 103 U 0.49 ∆E
PANTONE 104 C 0.48 ∆E PANTONE 104 U 0.92 ∆E
PANTONE 105 C 0.80 ∆E PANTONE 105 U 1.07 ∆E (more…)
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