ISO 12647 Reference Profiles
ISO 12647 Reference Profiles
- Subject: ISO 12647 Reference Profiles
- From: Henrik Holmegaard <email@hidden>
- Date: Sun, 24 Jun 2001 09:32:32 +0200
Dick Busher <email@hidden> wrote:
I spoke with a tech support person from Best who said that Designer
Edition only supported canned output profiles for the various machines
it worked with. Custom input profiles were fine, but custom output
profiles were not. No info on whether improvements were expected.
BESTColor ships with what the BEST folks call 'Reference Profiles'.
These profiles are built from the standard measurement sets you can
download free of charge from www.fogra.org. Four sets for positive
process and four for negative process on the press.
In order to verify that your proof is a proof the press is able to
hit, you can load the FOGRA TIFF CMYK control strip into BESTColor
and color convert it from the source ISO 12647 Reference Profile to
the destination inkjet Paper Profile.
You then measure the control strip with your spectrophotometer, and
plug the values into the Excel spreadsheet that ships with the FOGRA
control strip.
The paper and ink values are defined as Lab in the spreadsheet
workflow, and the spreadsheet tells you if the tolerance is
overstepped. You need to measure 2 x 17 patches and key or paste the
values into the spreadsheet. It takes about 15 minutes.
The ECI is discussing whether the tolerances are too loose, and a new
printing standard is on the way from the Federation of Print and
Media (: Bundesverband Druck & Medien).
The control strip is available as TIFF and EPS CMYK, and TIFF and EPS
Lab (for checking your gamut mapping, not for checking your proof).
My quibble with the good folks at BEST is that they fail to
communicate to the world at large what exactly those Reference
Profiles are. Like so many others, they believe that users don't
really want to know what they are using -:).
However, there is a reason why FOGRA posts 8 and not 4 data sets. The
dot gain on the press is different for positive and negative process.
It would be more meaningful if BEST named the profiles the same as
the original FOGRA data, COMMSP1 - COMMSP4 for positive on four
different papers at 60 l/cm, and COMMSP5 - COMMSP8 for negative on
four different papers at 60 l/cm.
Also, if you are running to a TROO1 press profile such as those Steve
Upton posts on his site, you can use the ISO FOGRA workflow just as
well. We had an offline chat with the FOGRA engineers over here about
this.
What is so very important about inkjet proofing is that the inkjet is
able to produce a gamut so much bigger than the press that it's like
a pinhead in a soccer pitch -:). There has to be some solid
instrument-based no-nonsense validation that shows both the designer
and the press operator that the inkjet print is indeed within the
gamut achievable by a press.
I've pushed the FOGRA data since 1998, and had off-line mails from
developers wanting access to the data for standard, bundled profiles.
However, none of this makes any practical difference if those who
bundle profiles for the ISO data don't write whether they are for
positive or negative process, and how to validate them in a proofing
situation.
(In case you guys think of FOGRA as 'just a printer's organization
hopping onto the ICC bandwagon', then best I recap that FOGRA is an
honorary member of the ICC because it was instrumental in getting
the founders talking in the first place, and for some very good
reasons -:).)