RE: Posterisation in a Press Profile + Standards
RE: Posterisation in a Press Profile + Standards
- Subject: RE: Posterisation in a Press Profile + Standards
- From: email@hidden
- Date: Thu, 08 Oct 2009 08:33:53 +1100
Roger,
It's like this. Any old scanner operator from the days of closed loop colour managed workflows (in a time before those
catchy phrases were invented) could tell you that the first thing they looked for on the job ticket was the printing
conditions. They then called up a table of presets based on an average, or optimum, for that printing condition. They then looked at the
copy and edited the preset based on its characteristics - high key, low key. The same applied to colour correction.
Colour management is, to me, about quality control, NOT copy correction. I have always been bemused by the
predilection for profile 'editing' when all that is required is editing the characteristics of an individual image for a given set
of printing conditions which are reflected in the profile. I always teach... RESPECT the profile. It's telling you something.
It is true that in some situations neither of these strategies will address the problem e.g. when highly saturated images end beside low key copy on the imposition. Sure, you can start twiddling the ink ducts amongst
other things but just remember that there are consequences. From my limited experience with printers they have more tricks in their back pocket for getting a result than a lot of poker players. That was their craft. But
the game has changed. Now they have to use those tricks to get consistency, not one-offs. As long as the customer is happy and nobody ends up in court it's all good.
Having said that a printing press is NOT an image editing or colour correction device. It is an instrument of mass production. Get it going in a reasonably straight line and it's easier to predict, especially if it's the same
line every day. Making allowances for copy characteristics happens BEFORE we go to press. Leave it to the image editors in Prepress. They are making their corrections based on the profile, standards based or
otherwise. Why make everybody's life more complicated than it needs to be?
Mark
On Wed, Oct 7th, 2009 at 12:00 PM, Roger <email@hidden> wrote:
> Hey Mark,
>
> I enjoyed reading your post. I'll put you in the "non-tedious" camp
> ;-)
>
> I remember first reading about press calibration a few years ago, and
> I can
> distinctly remember how that concept was just an anathema to me back
> then.
> Today, it's become a mantra. Not a panacea but a way of living --
> peace
> brother. Why can't a printing press be treated like any other device?
> It
> seems to be an idea that took a long time to take shape among
> printers in
> North America, everyone was printing to their own house standards
> trying to
> outdo the other guy.
>
> Having said that, it worth pushing the idea of calibration a little
> further.
> To me, there is "calibration" and there is "calibration". Duh! My
> hypothesis
> is that a press "calibration" isn't an absolute in itself. On a
> given
> substrate, using a given set of ink, at a given ink/water balance, at
> a
> given press speed, using a given set of blankets, using a given set
> of plate
> curving, it seems to me that various ink coverages, caused by various
> kinds
> of imagery (low, normal or high key), require different volumes of
> ink
> distribution, in order to match a certain proof standard. So, in a
> sense, it
> would seem incomplete, in my view, to talk about press calibration
> without
> also referring to the accompanying "ink load": at what ink level was
> a given
> press sheet/calibration obtained, I think is the interesting
> question. It
> may sound crazy but I run into this situation every day. To print
> "normal
> key" images, the press draws ink volume X from the ink train. If we
> were to
> stop the press abruptly, to measure the amount of ink on the rollers,
> we'd
> probably find a certain thickness, which can be measured. But to
> print "high
> key' images, the press does not need to draw as much ink from the ink
> train,
> thereby changing, in my opinion, it's ink response (I don't know how
> to
> better word this). This differential ink load, IMO, is the reason why
> a
> given calibration cannot be universal or absolute, in its capacity to
> bring
> a printing system to a "known" state. It is my belief that
> calibration is
> imagery-dependent. Can a printer develop different calibrations for
> the
> broader categories of printing? That would be pushing. But it would
> be
> interested to experiment.
>
> Have you ever ran into these situations yourself? Does the phenomena
> I
> describe sound rubbish to you?
>
> Haven't found much in the literature on this subject... Yet, it is a
> real
> problem.
>
> Best / Roger
>
>
>
>
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