Re: Pre-Linearization or Iterative Profiling (WAS Re: Printer profile mis-shape?)
Re: Pre-Linearization or Iterative Profiling (WAS Re: Printer profile mis-shape?)
- Subject: Re: Pre-Linearization or Iterative Profiling (WAS Re: Printer profile mis-shape?)
- From: Marco Ugolini <email@hidden>
- Date: Mon, 28 Aug 2006 13:49:53 -0700
In a message dated 8/28/06 12:50 PM, Scott Martin wrote:
> The documentation reads: "Using linearization data is not recommended unless
> the printer or its associated RIP does not have its own linearization option"
> Perhaps it should read something like: "Using linearization data is
> recommended when optimal linearization and gray balance is needed. This
> feature can be used in conjunction with a printer or RIP's own linearization
> option." After all, 90% of the time I use it, its with a device that does have
> its own linearization option.
The way I understand it (my apologies if my language turns out not to be
completely appropriate), this "pre-linearization" (PL) of the target does
nothing more than just change what color numbers are being sent to the
printer when one prints the target.
Say that patch 3 in row one of your RGB target reads R 170, G 170, B 0
before PL. After PL, the patch may R 194, G 165, B 0 instead. A majority of
the other patches in the target will also change values, to some extent.
But this doesn't "linearize" your device in any way: it only sends numbers
(this is the way I understand it) that will output colors on that device
that, once measured, will be closer to the nodes in the profile's tables
describing its output. The point is to facilitate the math inside the
profile, so that the nodes and the interpolations are more precise and more
reflective of the actual behavior of the device, producing results that are
both smoother and more neutral.
To recap, PL generates a new set of color numbers in lieu of the original
set of color numbers in the target. This target is then printed on the
device, and hopefully the measurements made from the modified target will
make the profiling software work more efficiently to describe the behavior
of the device. But in no way this "linearizes" anything. I don't see how
this "pre-linearized" set of target colors would interfere with the
linearization from a RIP, though I would think it advisable to linearize the
RIP first, *then* build the "pre-linearized" target from that RIP's
internally linearized output.
Being that I'm neither a mathematician nor a scientist, I can't explain it
better than that. And if I made any errors in my description, I would kindly
ask to be corrected.
Thank you, and regards.
--------------
Marco Ugolini
Mill Valley, CA
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