Subject: Re: optimum file resolution for Iris Printing
Regarding Geoffrey's remarks about Liquid Image's preference for RGB
files (as opposed to CMYK) and his assumption that we convert files "on
the fly":
Liquid Image has its own custom RGB > CMYK conversion which has been
optimized for our Iris 3047 printer, and will retain a far larger
portion of the RGB color space than the Photoshop conversion, which is
optimized for offset lithography. We put our clients' RGB files through
this conversion prior to sending the file to the Iris.
In traditional 4 color printing processes, plates are coated with ink
and this ink is transferred to the paper involved with a press. If the
aggregate maximum density of the ink exceeds 300% (ie, 75% per color on
average) the result is a muddy print. In inkjet printing, ink is applied
directly to the paper as a fine spray, and hence can reach densities of
100% per color (400% total) with no risk of muddy plates.
In practical terms, this means that a far larger CMYK color space is
available to artists printing on the Iris than what the Photoshop
conversion will alllow them.
Naturally, this assumes that the artist sees the Iris print as a final
product, not a proof of something ultimately intended for offset
printing. Also, it assumes that the source scan or artwork was produced
in RGB, which is often the case. In the case of a CMYK scan we would
naturally advise artists to leave their work in that colorspace.
Geoffrey is betraying an orientation towards, as he puts it, "digital
proofing", which entails respecting the limitations of traditional
printing presses. At Liquid Image, we generally cater to digital fine
artists and photographers who see the Iris print as the final work of
art, and hence are not interested in confining their palettes to the
tiny colorspace of the Photoshop CMYK conversion.
sincerely,
Bob Malkin (president) and
Kevin Mutch (creative director)
http://www.liquidimage.com
Liquid Image
1213 Third Street Promenade
Santa Monica, CA 90401
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