From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1Pu57M-0005OP-2E for garchives@archives.gentoo.org; Mon, 28 Feb 2011 15:34:37 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id D8F54E02CB; Mon, 28 Feb 2011 15:33:10 +0000 (UTC) Received: from sentinel.math.Princeton.EDU (sentinel.math.Princeton.EDU [128.112.16.31]) by pigeon.gentoo.org (Postfix) with ESMTP id AEBDBE02CB for ; Mon, 28 Feb 2011 15:33:10 +0000 (UTC) Received: from math.princeton.edu ([128.112.18.16]) by sentinel.math.Princeton.EDU with esmtp (Exim 4.69) (envelope-from ) id 1Pu55x-0003Cb-Fp for gentoo-user@lists.gentoo.org; Mon, 28 Feb 2011 10:33:10 -0500 Received: by math.princeton.edu (Postfix, from userid 1737) id 705D0C1CE1; Mon, 28 Feb 2011 10:33:09 -0500 (EST) Date: Mon, 28 Feb 2011 10:33:09 -0500 From: Willie Wong To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Re: [OT] Re: PDF: convert to grayscale Message-ID: <20110228153309.GA8766@math.princeton.edu> References: <87ipwuiqjr.fsf@ist.utl.pt> <4D559EB0.10902@orlitzky.com> <87wrkle2nr.fsf_-_@ist.utl.pt> Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-12-10) X-Archives-Salt: X-Archives-Hash: 4a0be306d3a468f3604f8cfc78f822d5 On Mon, Feb 28, 2011 at 03:08:23PM +0000, Grant Edwards wrote: > > That makes me wonder... in a color printer, I expect it not to print any > > color when it has no color ink, but do grayscale printers apply some > > conversion internally, to make sure that e.g. plain cyan is still > > visible (instead of making it white)? > > No. > > No matter what transformation you use from a 3-dimensional space into > a 1-dimensional space, there will be sets of values that differ in the > 3-dimensional space which map to identical values in the 1-dimensional > space. But it is trivial to make a transformation that maps to certain sets of values not more than once. In particular, there's nothing barring the printer to make it so that only pure white and pure black gets mapped to white and black, and everything else maps (nonuniquely) to a shade of grey. W -- Willie W. Wong wwong@math.princeton.edu Data aequatione quotcunque fluentes quantitae involvente fluxiones invenire et vice versa ~~~ I. Newton