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?

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Which proof profile for corrugated plastic posters and election posters?

As is well known, elections are always around the corner, and the trend towards ever larger and more numerous election posters is unbroken. In the past, only Mother Nature made the landscapes colourful in spring, but today every local, state, federal and European election does so easily. Every candidate, every large or small party now has the technical and financial means to transform entire streets into a colourful sea of messages and faces. Once the photographer has captured the election candidates well in the studio, the pictures go off for retouching and then for layout.

Until a few years ago, election posters were usually produced in classic offset printing and then glued onto hardboard with paste, drilled or screwed onto roof batten stands and then attached to street lamps with wire. And if the election took place in the summer, the posters were printed in a double edition, so that in an emergency the faded prints could be pasted over and refreshed with new ones after one month for the final spurt.

Today, however, the corrugated plastic poster is becoming more and more popular, as it is supplied pre-drilled and ready to use, retains its colour for several months and can be attached to street lamps with cable ties. But how should print data be created and how should data be prepared and proofed?

All manufacturers of corrugated plastic posters and election posters known to us want proofs in ISOCoatedV2 or ISOCoatedV2 300%

Corrugated plastic posters are produced on different systems. Sometimes four colours are used, sometimes six, sometimes more colours. Therefore, there are no binding proof standards for most digital print products produced in this way.

Instead, it works the other way around: Since most of these digital printing systems have at least the colour gamut of offset printing on picture printing paper, these printing systems are based on the established colour gamut of ISOCoatedV2.

For example, Printpartner-XXL writes: “For colour-critical motifs, we therefore recommend a prepress proof on the original material or the delivery of a colour-binding proof (with media wedge and date). Data that is delivered without colour information is provided and produced with the standard profile “ISO Coated v2”. In such a case, a colour complaint cannot be accepted.
Eine Reklamation der Farbe kann in so einem Fall nicht anerkannt werden.

From our point of view, most printing specialists demand ISOCoatedV2, some like flyeralarm and wir-machen-druck ISOCoatedV2 300%. Some want black exclusively as pure black, some exclusively as CMYK 50/50/50/100 colour black … and some do not give any information about the required colour profiles … but if you don’t specify anything, you probably won’t stick to anything … so if you want to be on the safe side, you should choose a supplier with a functioning colour management system and specifications for colour profiles.

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