[Openicc] What is exactly needed: Embedded Profile in CUPS raster !!

Robert Krawitz rlk at alum.mit.edu
Mon Jun 6 17:07:40 PDT 2011

On Mon, 6 Jun 2011 09:31:14 -0600, Chris Murphy wrote:
> For Epsons, they consider 180 dpi and 360 dpi to be "Draft"
> modes. Anything higher, such as 720 dpi is "Fine" or "Photo".

It varies.  On printers like the 2880, 720 DPI is very good on most
papers and 1440x720 DPI is really good (the printer can use the
smallest drop sizes at those resolutions).  On the R1900, you need to
be up at 1440x1440 to use the smallest drop size, and that on a
printer that doesn't have light inks.  Light inks typically yield a 3x
reduction in grain, so the smallest drops on the R1900 are roughly
equivalent grain-wise to 4.5 pl -- bigger drops than the 2880 or 3880.

At 1440x720, the smallest drops on the R1900 are 3 pl, which is about
equivalent to 9 pl on a CcMmYK printer -- basically the same as the
Stylus Photo EX.  At 720 DPI, we have to use even larger drops --
about 7 pl smallest drop size, looking at the numbers.  That's better
than the Epson Stylus Color 3000 (10 pl), but not by very much.

(BTW, Gutenprint uses slightly different terminology: Fast Economy is
usually 180 DPI or so, Economy is about 360x180, Draft is 360,
Standard is 720x360, High is 720, Photo is 1440x720, Super Photo is
1440x1440, Ultra Photo is 2880x2880, and Best is the very highest the
printer supports -- anywhere from 720x360 DPI on some ancient machines
to 5760x2880 on most of the current printers.  But it amounts to the
same thing.)

> On Jun 6, 2011, at 9:29 AM, edmund ronald wrote:
>> Chris, 
>>  With all due respect, and speaking as a photographer, I am very happy with what comes out of my Epsons at 720dpi, and when printing on matte media I don't run them any finer; the prints are of the quality *I* need. 
>>  Proofing may require super-resolution over a huge sheet, because that huge sheet is many many pages, but I believe fine art printing does not always require hi-rez once one cranks up the format on textured media. 
>>  Edmund
>> On Mon, Jun 6, 2011 at 5:13 PM, Chris Murphy <lists at colorremedies.com> wrote:
>> On Jun 6, 2011, at 7:39 AM, Richard Hughes wrote:
>> > On 6 June 2011 14:21, Chris Murphy <lists at colorremedies.com> wrote:
>> >> I'm unaware of any product that enables this inclusion of metadata.
>> >
>> > At the moment I'm working on another patch to GTK to be able to get
>> > the internal state of the print dialog, which data I can use in
>> > gcm-calibrate to add to the profile. I've still not decided on
>> > metadata names, but I'm figuring just using the cupsICCQualifier
>> > names, e.g. "cups_OutputMode" and then specifying lists using
>> > "Normal,Draft,Best" as the key value.
>> >
>> > From a technical point of view, I'm planning to use argyllcms to
>> > generate the profile, then open it in lcms in gcm-calibrate and add
>> > the few DICT entries we need.
>> OK but I'd say an ICC profile for a "Draft" mode on a printer is almost certainly useless. And might be questionable for "Normal". Almost certainly useful to build an ICC profile for "Best". However, an Epson printer doesn't use these terms, except for Draft. Everything else is "Fine" "Photo" "Superphoto" etc. Or there are specific resolutions specified. I surmise most inkjet printers are in the same boat, especially photo printers.
>> So even if this information is included I'm not sure how helpful it is. Draft and Normal may not have profiles for them at all. While Best might need two or three profiles if there are multiple resolutions available providing meaningful behavioral differences requiring unique profiles for those settings.

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