We spectrally measured the paper white tone and the proportion of optical brighteners of over 1,000 papers of the most important paper manufacturers such as Berberich and Papier Union as well as online printing companies such as Flyeralarm and wir-machen-druck.de.
Only a few paper manufacturers currently publish data on paper whiteness and the proportion of optical brighteners in their papers, but only technical indicators such as whiteness according to ISO 2470-2 or CIE ISO 11475. However, designers can hardly record paper whiteness with these values. In addition, it is not possible to read from these data whether and what proportion of optical brighteners the paper has.
Example above: Spectral data comparison of Antalis Coqueror CX 22 white for the measurement standards M0 and M1. Below you can also see the color deviation in Delta-E00 of 1.97 and the two paper white values in LAB and LCH.
Left: CGATS.17 Data for measurement conditions M1 and M0 for paper Antalis Conqueror CX 22 white
We have therefore measured the most important papers and dyes of all central paper producers and paper distributors as well as online printers in the three measurement standards M0, M1 and M2. From the difference in the paper whiteness of the two measurements M2 (UV cut without UV portion) and M1 (ISO 3664:2009 with noticeable UV portion), we determined the color distance on the yellow-blue axis of LAB in Delta-b and derived from this the proportion of optical brighteners according to Delta-B according to ISO 15397 and evaluated it.
Parallel to the images of the spectra, we have also provided spectral data in CGATS format for the measurement modes M0, M1 and M2, which can be downloaded for any paper. These values can be used, for example, in proofing software to calculate a paper white simulation for a specific production paper.
Since 2009 PSOUncoated has been the standard profile for uncoated paper. Nevertheless, proof service providers often have the problem that at first glance proofs on PSOUncoated often differ significantly from the print result. Immediately visible: the white point of the paper.
The PSOUncoated paper white looks very grayish. If, for example, PSOUncoated is proofed on an EFI 9120 XF paper, which actually has a neutral white coloration as paper, then the paper must be recolored by the printer in terms of paper white. This paper-white simulation makes the proof look “grayish” and often not “bright white” like the real production paper. “I can’t put this down to my client” proof service providers often hear from the agencies and designers who commission proofs. And frankly, printing on bright white uncoated paper will also differ significantly from the PSOUncoated Proof result depending on the paper selected.
Some proofing services still proof uncoated paper according to ISOUncoated, because the paper tone is much whiter and not so grayish. In the medium term, however, this will not overcome the misery: PSOUncoated is the current standard according to which the process standard for offset printing certified print shops are also based. But in the pressroom the differences between norm and reality often become apparent. If the new D50 standard light according to ISO 3664:2009 with higher UV components is used for inspection at the printing table, then proof and printing result can often only be matched very poorly. And due to the long standardization periods, this problem will continue to accompany printers and proofing service providers for quite some time to come.