[argyllcms] Re: Profiling flexo presses
- From: Roberto Michelena <colorsync@xxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 23 Aug 2005 09:38:05 -0500
> It may seem that such approaches would give the best,
> most accurate results, but in practice this may not
> be the case. The reasons are inaccuracy in the measurements,
> sampling "noise", and not using "typical device behaviour"
> information.
I used to judge the quality of the A2B table of a profile, by its
correspondance with the original sample data; furthermore, being that
sometimes the sample data was exactly the gridpoints (evenly spaced
target), why wouldn't the A2B table be just a dump of such data?
I understand 'inaccuracy in the measurements"; and supposedly making 4
or more measurements of the same target, then doing an intelligent
average (discarding stray samples), should get rid of such inaccuracy.
What do you mean by "sampling noise"?
For the "typical device behaviour" part I'm a little more skeptic. If
building an A2B of an offset press or a laminate proof, there's some
smoothness to be expected -because they're analog processes- and
therefore the samples should exhibit reasonable behaviour, and you
should correct them if they don't (like PrintOpen's "automatically
correct measurements").
But nowadays, what can you call typical in inkjets? with ink and paper
technology ever changing, ultrachrome inks, gloss differential,
swellable papers... CMYKRGB printers, variable drops, etc etc...
there's very little that can be assumed about them, and smoothness
might not be for granted. So doesn't it make more sense to just leave
the data as-is, maybe after averaging some prints and/or measurements?
-- Roberto Michelena
Infinitek
Lima, Peru
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