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Don't
be lost in the desert and buy sand ;-)
Again,
many new products claim to manage to the miracle of simulating colors of
offset presses while respecting their dot screening! Wonderful progress
of on demand ink jet would finally have authorized this miracle -
intended to preview the possible moiré effects on proof - whereas the
very expensive and slow continuous ink-jet printers - even being much
more accurate - never reached that point!
This
is illusory for the following reasons:
Ink
Jet printers Inks use much purer reflection spectra CMY primary colors
than offset, and this in order to be able to simulate the colors of any
offset-printed paper thanks to a broader color gamut.
For
example, an offset magenta 50 % (M50%) apparent color will be simulated
(under ISO D50 lighting) thanks to a suitable mixture of C'M'Y'K' inks
of the printer. It is obvious that one could not at the same time
respect the dot screening of the offset press and get the same color.
However,
let us go further! Let us imagine the Ink Jet printer is using same inks
and same paper as the offset press: this condition would be necessary
but not enough to get same colors while having the same screen dots,
because the optical part of dot gain largely depends on the penetration
depth of inks in paper, and thus on the order and method for the inks application
on paper. One would approach the press colors without reaching a
good accuracy.
In
conclusion, ink-jet proofing systems (or at least their PostScript RIP), which
claim to simulate offset screening, certainly use a screening
more resembling the traditional A.M. offset press screening, but this
dot screening remains very different from the press and would produce different
colors even if it would be the same.
What
is a real problem, once more in the field of the Color Proofing and
Graphic Industries, is that Product Marketing is using a very vague and
unsuitable vocabulary, which darkens reality and masks the true
technical and commercial stakes of modern Graphic Industries.
Concerning Color Proofing, the real productivity (expressed in square
meters per hour!), the capital investment cost, and yet more important the cost of
operation (Price of inks, paper, and maintenance), are much more important for the End User, plus many other basics needs
that are not
fulfilled yet by the most expensive systems!
At
the time of full digital prepress production workflows, it becomes
particularly uninteresting to polarize on detail specifications of color
proofing, which moreover are not met. In addition, it becomes SO easy to
print offset with stochastic screening...which may close all debates!
Last
word: In
real world, it has always belonged to the printing press to simulate the Customers' color
proofs (and NOT the reverse). And today, the appropriate Color Management
tools are existing!
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