Re: solid K or open K
Re: solid K or open K
- Subject: Re: solid K or open K
- From: David Wollmann <email@hidden>
- Date: Mon, 04 Nov 2002 19:48:31 -0700
- Organization: Luna Vista Imaging
Peter Merck wrote:
>
(In Onyx PosterShop 5.6.1)
>
The second one is to build a grey balance profile for use in 'advanced'
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settings for 'Job Profiles' in the server. I tried this one once, never
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figured it out completely.
>
>
I've experimented a little with this and also adjusting the N-factor
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setting. This helped a little for minor tweaks, but I went further and
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reprofiled and the resulting file looked the same as before the N-factor
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change. So the profile just readjusted the image back.
Since I build my profiles in Onyx, I have the full package, I have never messed
with the Gray Balance selection that comes up after you read the patches for
your linearization file. Plus it seems the only way to access that option is
after printing and reading the patches but before you actually build the
linearization step. If you are not building an ICC profile then I guess you
just use the linearization step and then proceed with the gray balance step and
then I think you are done. So your media would be calibrated but not fully
characterized.
Since I use the ICC method I can not use this gray balance option.
N-factor is not something I have messed with much either. I think it was more
useful prior to version 5 of Onyx PosterShop. Version 4 had a different method
of coming up with a media models and you had to always borrow a media model
from some other supplied media that was similar, plus then you needed to do
some additional tweaks to density settings in a window deep in the media model
dialogs. You could not see your changes until you had applied them and come out
of that window. Then if you did not like the look of your new curve you went
back in and tweaked again. If all that did not work you could also adjust the
N-Factor.
My notes on N-factor (for version 4.5) were as follows; a good starting point
was
Cyan 1.4
Magenta 1.4
Yellow 1.2
Black 1.1
A higher N-factor will straighten out the midtone portion of the linearization.
I thought I had a range for these settings in my notes but can not locate it
now. I do remember looking at some of the prebuilt profiles that were supplied
by Onyx for ColorSpan printers and I could not take cues from them as they
sometimes were outside the parameters that Onyx had given me.
I also have listed in my notes that "Scale" will affect the overall balance, I
am assuming that if my grays are looking a bit magenta then I would set the
scale setting for magenta lower than 100% or if I wanted to add some magenta
then I would use a setting higher then 100%.
The N-factor always sets it's own numbers automatically based on your readings
and these days with the way version 5 handles the media model I never look at
the N-factor numbers anymore.
>
>The next thing I want some answers
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> on is the check box in the Ink Limit dialog window that allows the GCR to
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> modify the settings (can not fully remember the wording) but I was told to
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use
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> this "Allow" setting from 4.0 to 3.5 and under that one should disable the
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> check box.
>
>
Haven't heard about unchecking the box for under 3.5 ink limit. From the
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book (we had so many at work I took one home for refernce) "If you want
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Postershop to adjust the GCR of the pixels within the image to meet the ink
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limit you just entered place a check the box below"
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I always leave this box blank so Postershop doesn't make any unknown
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adjustments to my file. Unknown to me anyhow.
Yea, one of the tech support guys at Onyx said this is the preferred method
when working with images, the box being checked on from 3.5 to 4.0. Doesn't
make sense to me though, shouldn't the GCR already be adjusting the file to
what ever your Ink Limit is? You can even leave the Ink Limit step out
completely and just do Linearization and then the ICC profile.
So, what I am wondering is if I tell it to not allow modification GCR to meet
Ink Limit is it then looking to the ICC profile for some type of limit for the
GCR to base it adjustments on? And, would this be an actually read value or
would it be the Ink Limit setting that one can assign in the building of the
ICC profile? (Also, if setting an Ink Limit this number should also be set in
the ICC Build Options dialog window.)
You build your profiles in Profile Maker if I remember, so you probably won't
be able to answer my question but I am hoping someone else can help.
The new Media Manager in Onyx, since version 5, is based on Profile Maker from
what I understand so maybe some of the settings are similar.
A new setting is called Black Width. Does anyone know how this alters the
blacks and when would it need to be adjusted?
>
One final question: Do you check the profiles of the incoming images?
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Sounds like you would, but I have had some people never check this.
>
>
Yes, we open up all the scans in Photoshop first to have a look and see if they
are tagged. If not tagged we look at a few different CMYK profiles and make a
judgment as to what looks good, and if they have supplied a print I will
compare my screen to the print to help in figuring out which profile looks
best.
If it is a profile other then my default choice assigned in the RIP then I will
convert the file to the default before Postscripting. If it is a tiff and is
not placed in Quark or some other page layout program I simply copy the tiff
over to the RIP computer and work with it directly.
Thanks,
David Wollmann.
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