diff options
Diffstat (limited to 'man/gimpprint-dithers.7.in')
| -rw-r--r-- | man/gimpprint-dithers.7.in | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/man/gimpprint-dithers.7.in b/man/gimpprint-dithers.7.in new file mode 100644 index 0000000..d6307c2 --- /dev/null +++ b/man/gimpprint-dithers.7.in @@ -0,0 +1,103 @@ +.\" t +.\" $Id: gimpprint-dithers.7.in,v 1.1.6.2 2003/08/22 23:31:56 rleigh Exp $ +.\" Copyright (C) 2000 Roger Leigh <roger@whinlatter.uklinux.net> +.\" +.\" This program is free software; you can redistribute it and/or modify +.\" it under the terms of the GNU General Public License as published by +.\" the Free Software Foundation; either version 2, or (at your option) +.\" any later version. +.\" +.\" This program is distributed in the hope that it will be useful, +.\" but WITHOUT ANY WARRANTY; without even the implied warranty of +.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +.\" GNU General Public License for more details. +.\" +.\" You should have received a copy of the GNU General Public License +.\" along with this program; if not, write to the Free Software +.\" Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. +.TH GIMPPRINT\-DITHERS 7 "@RELEASE_DATE@" "Version @GIMPPRINT_VERSION@" "Gimp-Print Manual Pages" +.SH NAME +gimpprint\-dithers \- Gimp-Print dither algorithms +.SH DESCRIPTION +Gimp-Print includes several dither algorithms. Dithering attempts to reproduce +various shades of gray (or all colors) from only a few different inks (black, +cyan, magenta, yellow, and sometimes light cyan and light magenta). The dots +can't vary in darkness or size (except for certain special printers), and so we +need to lay down a certain fraction of dots to represent each distinct level. +Different dither algorithms are suited to different purposes, and some are +significantly faster than others. +.SH DITHER ALGORITHMS +.TS +li li +lb l. +Dither Algorithm Description +_ +Adaptive Adaptive Hybrid +EvenTone EvenTone screening (experimental) +Ordered Ordered +Fast Fast +VeryFast Very Fast +Floyd Hybrid Floyd-Steinberg +.TE +.PP +For the highest quality, we recommend use of \fIAdaptive Hybrid\fP dithering. +For continuous tone images, \fIOrdered\fP works just as well and is somewhat +faster. Ordered dithering yields noticeably inferior results with text and +intricate line art, particularly at high resolutions. +.PP +\fIEvenTone\fP dithering is a relatively new screening technology developed by +Raph Levien. It offers superior smoothness in highlights and midtones, and +increased accuracy in shadows, resulting in significantly improved results +overall. The version of EvenTone dithering that we are using is enhanced with +some additional improvements we have made. It currently only operates with +CMYK (4, 6, or 7 color output) with RGB input, and should be considered +experimental. Note that it is patented (see US patent 5917614), but it is +licensed for use with GPL software. See http://www.levien.com/patents.html for +more information. +.PP +\fIFast\fP dithering, which is a simplified version of ordered dither, is +significantly faster, but color accuracy is worse, particularly on six color +printers and printer using variable dot sizes. On simple four color printers, +the quality is quite reasonable, although color printing will show more +speckling in dark tones than Ordered dither. For single dot size printers, +printing grayscale, this algorithm yields almost identical results to Ordered +with some performance improvement. On three color printers, the results should +be very similar to Ordered. +.PP +\fIVery Fast\fP is even faster than Fast, with even more loss of quality. It +shows even more speckling, and the output is heavily patterned. On laser +printers, and possibly on certain kinds of text and line art, Very Fast +dithering may actually yield the best quality. +.PP +\fIError diffusion\fP algorithms (\fIHybrid Floyd-Steinberg\fP is such an +algorithm) perform very well at high densities, and are capable of rendering +very fine detail well, but they tend to exhibit artifacts in the form of +"waves" or "worms" of dots which results in noticeable texturing in pale areas. +Furthermore, pale areas immediately adjacent to white take a while to "build +up" sufficient error to print at all. This is sometimes called "tearing". Its +use is not recommended. +.SH COPYRIGHT +Copyright \(co 2001 Michael Sweet (mike@easysw.com) and Robert Krawitz +(rlk@alum.mit.edu) +.PP +This program is free software; you can redistribute it and/or modify it under +the terms of the GNU General Public License as published by the Free Software +Foundation; either version 2 of the License, or (at your option) any later +version. +.PP +This manual page was written by Roger Leigh (roger@whinlatter.uklinux.net) +.SH SEE ALSO +.BR gimpprint\-color (7), +.BR gimpprint\-imagetypes (7), +.BR gimpprint\-inktypes (7), +.BR gimpprint\-mediasizes (7), +.BR gimpprint\-mediasources (7), +.BR gimpprint\-mediatypes (7), +.BR gimpprint\-models (7), +.BR gimpprint\-resolutions (7). +.\"# +.\"# The following sets edit modes for GNU EMACS +.\"# Local Variables: +.\"# mode:nroff +.\"# fill-column:79 +.\"# End: |