Re: G7 press calibration, best press conditions or average?
Re: G7 press calibration, best press conditions or average?
- Subject: Re: G7 press calibration, best press conditions or average?
- From: Mike Eddington <email@hidden>
- Date: Fri, 7 Nov 2008 14:31:48 -0500
You are correct in so far as it *might* be a mistake to dismiss or
underestimate G7. But, it would be equally incorrect to assume that
there are not already methods that are just as satisfactory.
Indeed it would. However, in my opinion what has been traditionally
less than satisfactory is the definition of the target itself. Density
and TVI alone as target are insufficient as there is no defined color,
and pigment load can vary the color of the end density. ISO 12647-2
defines CIELab for solids, but the TVI definition for tonality, since
based on an undefined solid and paper density is a bit ambiguous IMO,
with gray balance undefined and secondary. Moreover, legacy practices
(positive or negative plates) of the geographic area in which one
happens to operate can be used to define which curve is appropriate.
The definition of solid Lab, gray balance, and an unambiguously
defined tonal response, coupled with the process agnostic approach
within G7 are, IMO, the greatest benefits. That said, once
colorimetric targets have been reached, switching to traditional
density and TVI metrics (determined from a qualified L*a*b*) is
perfectly acceptable for production. I would add, however, that
control metrics such as the HR (midtone gray) patch allow a very quick
assessment of print quality at midtone (one L*a*b* reading), as
opposed to individual TVI measurements (multiple measurements per
channel).
It further begs the "calibration" term for which I am tiring, but
still do not accept.
Admittedly the scientific community usually reserves the term
"calibration" for measuring/graduating instruments, and differentiates
adjustment processes. However, the de facto definition for calibration
for the rest of us has come to include adjustment of devices or
processes allowing comparisons with other data, particularly
standards. As such, I personally have no qualms using the term
"calibration" to describe G7 or other methodologies, if not for the
fact that I now know it bothers some (or maybe despite the fact). ;)
Now, where did I leave those qualms.
Mike
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden