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?

As the paper white of the edition paper was determined by Papier-Union and the proof standard ISOUncoatedYellowish turned out to be suitable, the next step was to check on which paper we would proof ISOUncoatedYellowish. Because once we know this, we can also check how well we can match the spot colour red tones of the HKS N on this paper. We also have an overview of this on the page Proofing Papers. There you will find a table showing which proof standard we proof on which paper.

In der Kopfzeile der Tabelle mit den Proofstandards stehen die jeweiligen Proofpapiere von Proof.de. In diesem Falle für ISOUncoatedYellowish: EFI 9120 XF
The header of the table with the proof standards contains the respective proof papers from Proofing.de. In this case for ISOUncoatedYellowish: EFI 9120 XF

Now that the proof paper was clear with EFI 9120 XF, we could move on to the last table: The precision of the colour reproduction of spot colours on our respective proof papers. These tables can be found on the page: PANTONE and HKS Proofing

Colour deviations when proofing HKS and PANTONE colours

Hier finden Sie die Farbabweichungen aller HKS und PANTONE Sonderfarben in Bezug auf das verwendete Proofmedium
Here you will find the colour deviations of all HKS and PANTONE spot colours in relation to the proof medium used. Click on “HKS N” to access the table of colour deviations of HKS N colours on EFI 9120 XF for the proof standard ISOUncoatedYellowish

Now we can move on to the last table: Color deviations of HKS N colors in proofing on EFI 9120 proof paper. Here our customer can check, even before the proof, how well we can technically match his HKS N spot colours in the proof. We can achieve his potential HKS N red tones very well with values well below Delta-E00 = 1, so a difference in the visual perception of his HKS N colours compared to the original HKS reference will be hardly visible.

Die HKS Rottöne neben HKS 13 N sind im Proof auf EFI 9120 XF sehr gut darstellbar. Ein Proof dieser Farben wird also recht akkurat ausfallen.
The HKS red tones next to HKS 13 N can be very well represented in the proof on EFI 9120 XF. A proof of these colours will therefore be quite accurate.

Conclusion: The measurement and analysis work of the last few months is paying off noticeably for our proofing customers.

This example clearly shows that our customers can use our paper-white tables and our tables with spot colour deviations in proofing to make competent preliminary decisions about the usefulness of a proof with spot colours and also inform their customers in advance about the accuracy of fit between the paper white of the proof and the production paper. And all this without ever having had a sheet of the production paper or a spot colour fan of the selected spot colour in their hands.

What we do not simulate in the concrete case should also be said at this point: If the customer now orders a proof with four HKS N spot colours in the proof standard ISOUncoatedYellowish, then he must be aware of the fact that we do not really simulate the paper white of the production paper Papier-Union Fly Cream but only the standard-compliant paper white value of the selected proof profile ISOUncoatedYellowish. What we also don’t simulate is the shift of the HKS N red tones in direction to yellow due to the chosen production paper or proof standards, as we concentrate on the LAB value of the spot colour definition of HKS N that is stored in the proof system. The red tones will therefore also appear somewhat warmer and more yellowish in the print run on Fly Cream than in the proof.

 

Matthias Betz

Matthias Betz

Born in 1970. Owner and CEO of Proof GmbH in Tübingen. Since the 1990s, Matthias is dealing with color management, proofing, standardized lightning technology, color-consistent work and soft proofing. He is a certified PDFX-ready Expert (X-1a and X-4) and a member of the examination board for media design at IHK Reutlingen. Proof GmbH is the first worldwide company certified for PSOCoatedV3 and PSOUncoatedV3 Contract Proofing.

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