[Openicc] Introduction

[Robert L Krawitz]

I just joined the list, at Kai-Uwe Behrmann's suggestion.

I am the project lead for Gutenprint (formerly known as Gimp-Print).
To be precise, the current stable release series (4.2) is still named
Gimp-Print, while the forthcoming release series (5.0), which is in
beta, is named Gutenprint.  Gutenprint is a suite of free source
printer drivers that currently supports over 600 printers, with
primary focus on inkjets (although we support a number of laser
printers in black and white).  My interest in color management, of
course, is for printing purposes.

I have particular interest in high bit depths (Gutenprint uses 16 bits
internally and supports 8 and 16 bit inputs), N-channel support (for
multi-tone printers, such as CcMmYK, and multi-hue printers, such as
CMYKRB or CMYKOG), and GCR/UCR.  Currently, Gutenprint uses fairly ad
hoc algorithms to perform color conversion, channel splitting (for
multi-tone printers), and extra hue generation.  The color adjustments
and extra hue generation are mostly performed in HSL space, and
channel splitting is performed by a fairly simple weighting procedure
that takes into account the total ink load.

Gutenprint offers a very large number of options, with a variety of
data types available, including integer, floating point, string,
curve, array, and counted raw.  The option system is highly
extensible.  The Gutenprint distribution package includes plugins for
the GIMP (1.2 and 2.x), an IJS-based driver for Ghostscript, a CUPS
driver package, Foomatic metadata support, and test programs and other
utilities.  It is written in C with minimal dependencies, and is
released under the GPL.  Third party packages that use Gimp-Print or
Gutenprint include CinePaint and Roy Harrington's QuadTone RIP.

The Gutenprint 5.0 architecture is considerably friendlier than the
4.2 architecture toward plugging in replacement color conversion
modules, although there is more work to be done in that area that will
probably be done in 5.1 for release in 5.2.  We currently support K,
W, RGB, CMY, CMYK, and (for Epson printers only thus far)
printer-specific raw inputs, which may or may not be linearized at the
user's discretion.  A variety of screening algorithms are supported.

We've struggled with color management for a while.  We originally
intended to release 5.0 with color management, but that hasn't worked
out, and 5.0 is already very late to plan.  I want to get the color
management interfaces right, since it's going to be very hard to undo
mistakes in this area.

Anyway, I look forward to interesting discussion on this list.

-- 
Robert Krawitz                                     <rlk at alum.mit.edu>

Tall Clubs International  --  http://www.tall.org/ or 1-888-IM-TALL-2
Member of the League for Programming Freedom -- mail lpf at uunet.uu.net
Project lead for Gimp Print   --    http://gimp-print.sourceforge.net

"Linux doesn't dictate how I work, I dictate how Linux works."
--Eric Crampton