As can be seen from the screen grabs from Chromix’s excellent ColorThinkPro tool, using the ISO coated v2 eci Fogra 39 based CMYK profile and the new PSO coated v3, Fogra 51 based profile, there are small changes to the CMYK Lab colours, the largest change is to the paper white, which is now more in line with most ISO PS 1 premium coated papers.
The changes from Fogra 39 to Fogra 51 profiles are slight. It is also likely that in the forthcoming changes to ISO 12647/7 contrat proofing, De2000 will be the only metric used.ĭe2000 is considered to be a more accurate method of measuring and calculating colour difference as it is weighted to reflect human colour perception.
The other change to measurement is that De76 as the metric for measuring colour difference can be changed to De2000. Proofing papers will also need to be changed to reflect the OBAs in the production papers and the white paper point in the profiles.
The M1 readings will also apply to proofs produced using these new profiles, to the ISO 12647/7 contract-proofing standard. The reason that M1 spectrophotometer readings are now used for this standard and the CMYK profiles is that its is more accurate when measuring stocks with high optical brighteners (OBAs), used to make papers and board appear whiter and brighter. So I think this new standard may have a slow introduction over the next 2-3 years as instrumentation is updated. Also many near line and in-line systems scanning spectrophotometers on presses do not yet support M1 readings. The main reason for this, IMHO, is that this new standard requires the use of M1 spectrophotometers, so the cost of this change could be high. I think it is fair to say, that at present there has not been a rush by printers and their clients to change to this new version of the standard and it’s associated new CMYK profiles. So now is a good time to look at the main differences between the older version of the standard ISO 12647/2-20, which used Fogra 39, coated, and Fogra 47, uncoated based CMYK profiles. And yes, it is a little odd that the coated one does not refer to Fogra 51 and the uncoated does refer to Fogra 52! The Fogra 51, coated, and 52, uncoated, colour datasets and the new CMYK ECI profiles made from these datasets, PSO coated v3 and PSO uncoated v3 Fogra52, were released at the end of last year. This latest version of ISO 12647/2 standard printing conditions for offset litho was published in late 2014.
0 kommentar(er)
