From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: DKIM-Filter: OpenDKIM Filter v2.11.0 stuffed.shaftnet.org 148NqI7o771133 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=shaftnet.org; s=default; t=1620517939; bh=OJP30AthJFKqwYlRuMU9ahL3fe0UILJZsuODSNvmqnA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Uw8v7eT6vsuJsEgE66TT9MgbM83+e2htGrUnUP2f+ZMmy77gB9u05xlG6Msl7h/Qs DFUaaAFY+1e4j1wWch7qjZ358Qu8/YeBgZTwR8TXweoDku23a97amrOrSQjD6QdGWS Fq2XLZYRVlAQSOMPprGm1FZm+9yFvWliZyIlTU5A= Date: Sat, 8 May 2021 19:52:18 -0400 From: Solomon Peachy Message-ID: References: <8c101e3b-2f80-666c-db86-05b7dd170a7c@gmail.com> <29E8A83D-5BBB-49AA-83A6-4B3EB765828A@msweet.org> <9db67beb-7ca2-249c-88e4-ead29d19ce63@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="P/4Zw/jmgq+QoxLh" Content-Disposition: inline In-Reply-To: Subject: Re: [Printing-architecture] Make use of extended color spaces on IPP printers List-Id: Printing architecture under linux List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Till Kamppeter Cc: "printing-architecture@lists.linux-foundation.org" , Jay Berkenbilt , Vikrant Malik --P/4Zw/jmgq+QoxLh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, May 08, 2021 at 12:11:51AM +0200, Till Kamppeter wrote: > WDYT, would it also make sense to also switch to Adobe RGB (if available = on > the printer) if the user sets print-quality=3Dhigh? The colorspace is a property of the submitted printjob. As transforms=20 into different colorspaces are inherently lossy, it must only be done if/when absolutely necessary. At the end of the day, there are only really three basic scenarios: 1) Printjob is submitted in the printer's native/preferred colorspace, eg due to a fully color-managed workflow. 2) Colorspace-aware printer that will parse embedded ICC profiles and transform data into the printer's native colorspace. 3) Non-colorspace-aware printer This leads to a handful of requirements: 1) It must be possible to tell the printer that the job is already in=20 its native/preferred colorspace. (It's called various things in=20 UIs, such as "disable color correction" or "host-managed color") 2) The job *must* support embedding an arbitrary ICC profile 3) If there is no embedded ICC profile and the "host managed color"=20 option is not set, just assume everything is sRGB Notes: * "Printer" and "Printer Application" are interchangeable here * "Printer native colorspace" is arbitrary, and defined by an ICC profile. With respect to (2), It seems the PWG raster format only defines a=20 handful of colorspaces via ColorSpaceEnum; eg DeviceRGB, sRGB, and=20 AdobeRGB. This is a weakness vs JPEG or PDF (which allows arbitrary=20 profiles. Can we rely on that ColorSpace field being set correctly? (In practice, IPP client UIs seem to be _very_ lacking when it comes to=20 exposing supported options...) - Solomon --=20 Solomon Peachy pizza at shaftnet dot org (email&xmpp) @pizza:shaftnet dot org (matrix) High Springs, FL speachy (freenode) --P/4Zw/jmgq+QoxLh Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEE3H5Sx9DyiyB5hnENrGLLO/XVulEFAmCXJC8ACgkQrGLLO/XV ulGfdxAAs0YQnWX39X9PdMoIUXbL9P2CdJg53bNaqFNc0KzxQOvOLVkTF4FjzBJC z9DRp8v9J/5qpqu2mETWwNWekBuDYvq8DpQPv1z3QES1hODfUP7zuaIZRhOKpMxu Zc1mnyUdiI0bboAZJbgAw3yks02NyB4AvPFnZfR2ujUE4NbY9WsinHP7fEBa8Moe nk8creEO+2bjjrZBCv7p3ZKiNfX8RGZyooJ2xbYmymo8WhOSyLOG+FsLerdgw/2o 6RF66yikFeBmAg4EChm6uQlybQmwbyCjHObB9asp9aMansuyIHTNKsJIcQbFXeKa xvUJEImp26mGTxwtYoAckCVa7BjMqDrdHkwpO+3yrSxOcuhkV8MObj1YhFAKvLQd WuhQgEap/5ZSkxEVXP2ixYYX5dwlWxc6Nn/HVWQZEzU/L2Dsr2uAqQIspv+ZJbV/ RzGCTTHSLcxfn0YTsP6G6OSIl+J20YTUF8sOiKTYCND155eAVlxqrZU1TjACYm5X EdfSZPZH2oM+HIRVngp9r0GdcSqc0NBmc5SSit4SSUkt9Onmzf885mrBGD/0IrsE 4nv0XVb0HHR2cpgAfeFqJUotUVgEAGB6wHH96PZux3b1lDs7ljfo2nxn/+9834He KMFhZr3upjej/8Gtxl1RExv8X/IUOyWIcBoWy48fcRnVi42hVW8= =vf81 -----END PGP SIGNATURE----- --P/4Zw/jmgq+QoxLh--