Re: Linearizing a press (was Re: Max K generation question)
Re: Linearizing a press (was Re: Max K generation question)
- Subject: Re: Linearizing a press (was Re: Max K generation question)
- From: Roger Breton <email@hidden>
- Date: Mon, 27 Sep 2004 19:42:38 -0400
Hi Terry, and Steve and Rich,
I am not arguing that a press is linearizable the way an imagesetter is! I
hope you don't think that I expect a 50% dot in Photoshop to print as 50%
dot area on press, using Murray-Davies. Please, have mercy. I did not mean
neither to say that everything should be done to make that behavior happen.
Dot growth is a naturally occuring phenomenon in the world of halftone
printing. In that context, all I'm saying is that, for superlative press
profiling, it is not enough to pin down the behavior of the 50% dot on plate
and press, expecting that the rest of the the tone curve will fall into
place on its own. That's not my experience.
What I'd like to see happen on a press, and what I believe is desirable, is
a nice monotonic dot growth pattern just like on a nicely linearized inkjet
printer, with no crossovers of any kinds (think BestColor linearization).
The secret of these smooth, graduated curves sure takes more tha pinning
down the 50% dot on a CTP system. It's a factor that is too easy to
overlook: all steps of the tone ramp should be managed for this to happen.
Does it involve iterations? Most likely. But is it worth it? I believe so.
Although I don't have empirical evidence to offer that this is so. It's just
my hypothesis.
>
I prefer the term "press optimization" where you measure the press's
>
current state using linear plates and then adjust the plate curves to
>
achieve a specific TVI (GRACoL/SWOP/whatver). This is the standard
>
process I go through in setting up a press prior to profiling it.
If by press optimization you mean a sort of audit activity prior to running
the characterization target to get the press to behave in an idealized
manner as far as dot growth is concerned, then this is exactly what I'm
talking about. Too many times, I must say, I've been stuck making profiles
for process I could clearly see were far from well-behaved. And despite of
all this, the profiles were still quite capable of producing good color. I
wonder how much more superior would the color matching have been if the tone
distribution pattern would have been more regular!
>
Now, if you're talking about linearizing a press using something other
>
than dot gain/TVI as a measure, then I'm all ears! I've had some ideas
>
in this area that I'd like to try but that I'm not ready to divulge
>
publicly.
OK. We'll wait for you ;-)
>
Cheers,
>
Terry
Regards,
Roger Breton | Laval, Canada | email@hidden
http://pages.infinit.net/graxx
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