Re: GMGColor .mx4 to icc profiles / Smoothing
Re: GMGColor .mx4 to icc profiles / Smoothing
- Subject: Re: GMGColor .mx4 to icc profiles / Smoothing
- From: Jan-Peter Homann <email@hidden>
- Date: Thu, 03 Jan 2008 13:00:44 +0100
Hello Matthew, hello list
Heidelberg PrintOpen offers good smoothing algorithms on the
measurement-data incl. visualization of the results and the possibility
to compare original and smoothed-data colorimetricly before the profile
is calculated.
Also the free Argyllcms offers several smoothing possibilities for user
which loves the terminal....
Of course the generation of profiles is doing some smoothing on the data
(espacially if small profile size is activated)
I had a lot of cases where smoothing the measurement-data was definitely
necessary, and the smoothing by only calculating an ICC-profile was not
enough.
I asked several times the last years Logo / GretagMacbeth now X-Rite to
implement this feature in Profilemaker , but nothing happened...
But I´m still hoping, we will see it sometimes in a X-Rite solution...
For every user, who is profiling print processes on high level, I
strongly recommend a solution offering smoothing of measurement-data
before the profile is generated. This is an absolut must in my eyes.
Regards
Jan-Peter
Matthew Larmour wrote:
Thanks Thomas.
Outside of GMG, is anyone smoothing measurement data prior to building conventional ICC profiles? Or is it really not required as profiling apps generally do this automatically prior to building the profile?
Matthew Larmour
----- Original Message -----
From: Thomas Holm/pixl <email@hidden>
Date: Wednesday, January 2, 2008 12:40 am
Subject: Re: GMGColor .mx4 to icc profiles
To: Matthew Larmour <email@hidden>
Cc: email@hidden
On 02/01/2008, at 01.02, Matthew Larmour wrote:
Hi Thomas,
Could you elaborate how you go about doing this? What sort of
a
"curve tool" do you use for this?
Sure:
In GMG's PRofile Editor make a new MX4, import either en ICC
profile
or LAB measurement data, select calculate with target (It
doesn't
matter much which gamut/printer select but it is preferable if
it is
well behaved (no inherent kinks)- such as Fogra 39 dataset.
Then in 4-D color view, under Tools open Graphic View (curve tool).
You are now looking at the cyan axis (all cyan grid points).
by
clicking on the right arrow under Magenta you can scroll through
all
combinations of CMY with no Black (when you hit 100% and keep
going
Yellow will automatically increase by 1 increment). After doing
this
select 20% K and repeat the procedure and then 40% K, repeat etc
and
then finish off with the Key axis.
What you are looking for, in a few words, is weird curves.
IE: If on some greenish color you have a smooth yellow curve,
but on
the next increment have one which at one spot is negative (say
50% has
a lower value then 40%) but on the next increment it is fine
again,
you almost certainly have a problem.
With some experience you can figure out whether you will need
to
smooth, or rather, how much. I find that even measurement data
for
inkjet printers which are pre linearized will benefit from
some
smoothing.
Hope this helps.
Med venlig hilsen
Thomas Holm / Pixl Aps
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