Re: 'The Shape of Colour' for Inkjets
Re: 'The Shape of Colour' for Inkjets
- Subject: Re: 'The Shape of Colour' for Inkjets
- From: Joel <email@hidden>
- Date: Thu, 25 Jan 2001 14:04:26 -0600
From: Rudy Vonk <email@hidden>
Reply-To: email@hidden
To: ColorSync List <email@hidden>,
email@hidden
Darrin <email@hidden> has me thotoughly confused here, and I
wonder if he is doing something wrong:
I have been making adjustments to the settings within Colorblind
Professional 3.6, building profiles with the 1441 patches, and I have
changed the setting from and to:
(detailed settings and results snipped)
Darrin, ColorBlind creates output patches *independently* of your black
generation settings (total dot, max black, black start, etc.). They do
this so that you can create new profiles with different settings from
the same readings. Therefore, in theory it is impossible for your
patches to *look* different if you output them correctly.
With variations in the settings that are "reasonable" (i.e. do not
substantially limit the ability of the printer to output its full gamut)
the statistics will not vary, but it is not "unreasonable" to expect a
little variation if you start cutting deeply into the printer's
capabilities (e.g. ignore black ink). However, I am still talking about
profiles made from *one* reading of *one* set of patches.
How does your scenario differ? Have you taken new readings from the same
patches for every change in setting? (Unnecessary, and could indicate an
inaccurate measuring device.) Did you print out new patches every time?
If these turned out different every time as you suggest, there is
something seriously wrong, either with your profiling workflow or with
your printer :-)
Are you sure that each time you put out the patches (also unnecessary)
you disable all color management in the RIP and with the same (or none
whatever) linearization curves?
--
Rudy is right in that GCR/UCR variations can be resolved reasonably
well with the same test swatch. This is why, on the differing results
in your test swatches issue, I think you need to back up and look at
your ink limits and subsequent two/three ink mixes. Mottling would
(and does) give you variables you speak of, and usually you can
visually check as you linearize, or measure and table with a
densitometer. With most media/ink combinations we've found if you
have to limit your ink to less than 60% of your printers total ink
limit then there is a media/ink compatibility issue. There are
scenarios (I use one for profiling double print applications) where
you can use less ink in your settings to "trick" the process, but I
don't recommend it for your purposes.
Single ink channel densities are relatively straight forward, but two
and three color amounts (mix) appear to be the hardest to nail down
with inkjets.
(Input required here from benign color deity.)
So Darrin, are you a'messin' with your ink limits and setting up a
reasonable Total Ink Limit before you print? (sorry I missed your
original post)
--
joel johnstone
designtype
Winnipeg Manitoba Canada
email: work: email@hidden
color geek in residence, reality notwithstanding