Re: Profile Editing Thoughts
Re: Profile Editing Thoughts
- Subject: Re: Profile Editing Thoughts
- From: Jan-Peter Homann <email@hidden>
- Date: Wed, 27 Jun 2001 13:58:14 +0200
Eric_Bullock wrote:
>
>
I should also give some
>
information on what we do. We are a small in-house pre-press department and
>
we do all of our own proofing on an IRIS 2PRINT running a TR001 SWOP
>
simulation. We have a profile of this device running the SWOP simulation on
>
a publication stock. We seperate all of our scans direcly into CMYK (using
>
the output profile of the proofer). We process all of our RGB digital
>
captures using the camera profile as source and the same IRIS profile as
>
destination. All of our monitors are calibrated to 50000K 1.8. Our CMYK
>
setup in Photoshop is the same output profile we use to convert to CMYK on
>
the scanner and in the digital capture conversion.
Hi Eric
You are just on the right way. But please make a little step back in history. If you bought a prepress scanner like crosfield 10 years
ago, there were 2 or 3 weeks training included. And scanning is mainly converting from RGB to CMYK.
Colormanagement is a far more complex field. The marketing guys sell colormanagement as out of the box solutions and not as a solution
with 4 weeks training in a production environment included.
In the professional business, all the colormanagement-tools have the target to come with less (!!!!) corrections to a visual good
result in separation, proof and print.
As it takes time to learn the classical tools of scanning and color correction, it take also time to understand the technology of
colormanagement. If the goal is to come with less corrections to a good visual result, it is adeqate to edit every profile in the
workflow, if you now what are you are doing. And the critical part is to know what are you doing. You can learn by try and error or
you can search a colormanagement-trainer with the same production background you have.
Compared to the price by buying profiles by an external service, or buying the measuring equipment incl. software for profiling, the
price for colormanagement-training should be 3 or 4 times higher calculated.
E.G. If you buy for 500 $ a monitor-profile and a profile for your proofer, you should calculate 1500 $ by training how to plan your
workflow, configure your software and how to use the profiles.
If you buy for 10.000 $ measurement-devices and software for profiling, you should calculate 30.000 $ for training including:
- how to plan your workflow including quality control
- how to calibrate/linearize before profiling
- how to make profiles
- how to inspect your own profiles and profiles you get from your partnerts
- how to edit profiles generally instead editing every picture
- how to edit profiles and predict the implications in the complete workflow
- how to document your edits, that you are able to understand 6 months later what you have done
- how to install systems of quality control with your partners and customers
- how to earn money by doing colormanagement-services for your partners and customers
Some tips for your case
One important thing is to understand how the whitepoint is measured and calculated in the profile.
If you measure a offsetprint with optical brighteners, you will get a whitepint with e.g. Lab b -4
In the profile, the whitepoint has his own tag (text field) which describes only the whitepoint. One more tag is the table CMYK->Lab
rel colorimetric. This table is calculated by the measurements from the testchart but the information for the whitepoint is subtracted
(mathematically not correct term) from every measurement patch.
The table CMYK->Lab relcol from the offsetprofile is used for softproofing and proofing with the absolut and the relative colorimetric
intent. With relativ colorimetric (soft)-proofing only the CMYK->Lab table will be used. With absolute colorimetric (soft)-proofing,
the whitepoint will be added (mathematically not correct term) to every entry in the CMYK-Lab table.
If you have an offsetprofile with a bluish whitepoint, your softproof will change from bluish to more yellow (and more lightness) if
you change from absolut to relative colorimetric softproof. An editing of the whitepoint will change the absolute colorimetric
softproof, but not the relative colorimetric version.
The case in proofing is more complicate, because you have also to look to the whitepoint and the Lab-CMYK table from the
proofing-profile.
This cases seem to be very complicated by reading them as a text. But with a good training including inspecting the profiles, doing
edits and looking at the results on the monitor and proofing device, it is easy to understand for a prepress professionals.
Greetings from berlin, germany
Jan-Peter
--
Jan-Peter Homann
mailto:email@hidden
http://www.colormanagement.de