From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.comp.tex.context/88088 Path: news.gmane.org!not-for-mail From: Joshua =?UTF-8?B?S3LDpG1lcg==?= Newsgroups: gmane.comp.tex.context Subject: Re: Which Image quality should I use ? Date: Sun, 13 Jul 2014 13:10:58 +0200 Message-ID: <20140713131058.291abc62@medea1.site> References: Reply-To: mailing list for ConTeXt users NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1405249913 6276 80.91.229.3 (13 Jul 2014 11:11:53 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 13 Jul 2014 11:11:53 +0000 (UTC) To: ntg-context-wvrSQK3plZs@public.gmane.org Original-X-From: ntg-context-bounces-wvrSQK3plZs@public.gmane.org Sun Jul 13 13:11:49 2014 Return-path: Envelope-to: gctc-ntg-context-518@m.gmane.org Original-Received: from balder.ntg.nl ([5.39.185.229]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1X6Hh4-00022B-Qe for gctc-ntg-context-518@m.gmane.org; Sun, 13 Jul 2014 13:11:46 +0200 Original-Received: from localhost (localhost [127.0.0.1]) by balder.ntg.nl (Postfix) with ESMTP id 842E4102E2 for ; Sun, 13 Jul 2014 13:11:46 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at balder.ntg.nl Original-Received: from balder.ntg.nl ([127.0.0.1]) by localhost (balder.ntg.nl [127.0.0.1]) (amavisd-new, port 10024) with LMTP id s59mLu6NtGQ5 for ; Sun, 13 Jul 2014 13:11:46 +0200 (CEST) Original-Received: from balder.ntg.nl (localhost [IPv6:::1]) by balder.ntg.nl (Postfix) with ESMTP id C47F610250 for ; Sun, 13 Jul 2014 13:11:38 +0200 (CEST) Original-Received: from localhost (localhost [127.0.0.1]) by balder.ntg.nl (Postfix) with ESMTP id 5F36F101EB for ; Sun, 13 Jul 2014 13:11:35 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at balder.ntg.nl Original-Received: from balder.ntg.nl ([127.0.0.1]) by localhost (balder.ntg.nl [127.0.0.1]) (amavisd-new, port 10024) with LMTP id AzTHL1Vq3D1y for ; Sun, 13 Jul 2014 13:11:32 +0200 (CEST) Original-Received: from filter2-ams.mf.surf.net (filter2-ams.mf.surf.net [192.87.102.70]) by balder.ntg.nl (Postfix) with ESMTP id 2BB77101E6 for ; Sun, 13 Jul 2014 13:11:32 +0200 (CEST) Original-Received: from plane.gmane.org (plane.gmane.org [80.91.229.3]) by filter2-ams.mf.surf.net (8.14.3/8.14.3/Debian-9.4) with ESMTP id s6DBBUbZ002165 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=NOT) for ; Sun, 13 Jul 2014 13:11:31 +0200 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1X6Hgo-0001j5-Bc for ntg-context-wvrSQK3plZs@public.gmane.org; Sun, 13 Jul 2014 13:11:30 +0200 Original-Received: from hsi-kbw-046-005-000-014.hsi8.kabel-badenwuerttemberg.de ([46.5.0.14]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sun, 13 Jul 2014 13:11:30 +0200 Original-Received: from joshua.kraemer by hsi-kbw-046-005-000-014.hsi8.kabel-badenwuerttemberg.de with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sun, 13 Jul 2014 13:11:30 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 26 Original-X-Complaints-To: usenet-dbVV3NMTNubNLxjTenLetw@public.gmane.org X-Gmane-NNTP-Posting-Host: hsi-kbw-046-005-000-014.hsi8.kabel-badenwuerttemberg.de X-Newsreader: Claws Mail 3.9.2 (GTK+ 2.24.22; i586-suse-linux-gnu) X-Archive: encrypt X-Bayes-Prob: 0.0001 (Score 0, tokens from: ntg-context-wvrSQK3plZs@public.gmane.org, base:default, @@RPTN) X-CanIt-Geo: ip=80.91.229.3; country=NO; latitude=62.0000; longitude=10.0000; http://maps.google.com/maps?q=62.0000,10.0000&z=6 X-CanItPRO-Stream: uu:ntg-context-wvrSQK3plZs@public.gmane.org (inherits from uu:default, base:default) X-Canit-Stats-ID: 0QMpLbvG6 - 9c33ceca05db - 20140713 (trained as not-spam) X-Scanned-By: CanIt (www . roaringpenguin . com) on 192.87.102.70 X-BeenThere: ntg-context-wvrSQK3plZs@public.gmane.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: mailing list for ConTeXt users List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: ntg-context-bounces-wvrSQK3plZs@public.gmane.org Original-Sender: ntg-context-bounces-wvrSQK3plZs@public.gmane.org Xref: news.gmane.org gmane.comp.tex.context:88088 Archived-At: On 2014-07-12, 14:58, Pol Stra wrote: > I wonder, what can I do to reduce the size of those files while > keeping a printable quality document? Besides reducing the resolution, you can reduce the number of colours used in a PNG picture, which is called colour quantization. For example, we can differentiate between ca. 12 levels of gray (between black and white) with our eyes. So it is useless to differentiate between hundreds of different colours in a gray picture. I quantize all my gray pictures to use 12 colours only, and the difference is usually not visible, but it leads to a much smaller file size. For coloured pictures, you need of course more different colours, you have to try different values with each picture to find the best number. I use the tool pngnq for quantization. After quantization, one can further losslessy compress an image by removing unnecessary meta informations from the file, which can be done automatically with the tool Trimage. I've got both pngnq and Trimage from the repositories of my Linux distribution. Kind regards, Joshua ___________________________________________________________________________________ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context-wvrSQK3plZs@public.gmane.org / http://www.ntg.nl/mailman/listinfo/ntg-context webpage : http://www.pragma-ade.nl / http://tex.aanhet.net archive : http://foundry.supelec.fr/projects/contextrev/ wiki : http://contextgarden.net ___________________________________________________________________________________