Re: Profiling Epson 2200/2100
Re: Profiling Epson 2200/2100
- Subject: Re: Profiling Epson 2200/2100
- From: Robert L Krawitz <email@hidden>
- Date: Mon, 5 Apr 2004 07:22:21 -0400
Date: Mon, 5 Apr 2004 03:12:19 -0500
From: "Dennis W. Manasco" <email@hidden>
At 11:35 am -0700 4/4/04, Andrew Rodney wrote:
>You'll want a profile for both output resolutions.
I thought that that would be the answer, but I had to give myself
some hope ;-)
I assume that the two profiles will be quite a bit different
internally because at 1440 dpi the printer has to lay down
significantly more ink in each droplet to achieve the same print
density it would get when printing at 1880 dpi. This greater ink
usage per droplet will then cause the mixture of inks in an image
area to be different at the two resolutions and thus alter the hue
and saturation.
Is this a reasonably correct and coherent precis of the reason to
profile at both resolutions?
The driver should take care of all of that for you, but it probably
doesn't do a perfect job of it. Basically, the 2200 uses sets of
three different drop sizes to print. The set used at 1440x720 is the
same set as used at 2880x1440, but at 2880x1440 DPI only the smallest
drop size of the set is required to completely fill the page. At
1440x720, the smallest drop size (4 pl) won't fill the page, so in
areas of higher density (darker midtones and shadows) the second drop
size (about 9 pl) has to be mixed with the smallest in order to
achieve full coverage. If the driver calibration is a bit off the
results won't perfectly match.
(Actually, at 2880x1440 the printer allows *only* the smallest drop
size -- 4 pl -- to be used; the driver couldn't use the larger drops
even if it wanted to. What's also interesting is that the 4 pl
smallest drop is able to achieve full coverage at 1440x1440 DPI. The
printer doesn't support this resolution, so we do it by printing on a
1440x1440 DPI subgrid within the 2880x1440 DPI printer grid. For a
variety of reasons that I'll go into if people want, 1440x1440 DPI can
be almost as fast as 1440x720 DPI, if the driver supports it.)
It's actually possible to use the same drop sizes at 720 DPI, but in
this case all three drop sizes (approximately 4 pl, 9 pl, and 20 pl)
are required. This means that the drop size transitions will be in
lighter midtones and may require yet another calibration. At lower
resolutions, different sets of drop sizes (I'd have to look at the
code to figure out the actual approximate numbers) are used.
--
Robert Krawitz <email@hidden>
Tall Clubs International --
http://www.tall.org/ or 1-888-IM-TALL-2
Member of the League for Programming Freedom -- mail email@hidden
Project lead for Gimp Print --
http://gimp-print.sourceforge.net
"Linux doesn't dictate how I work, I dictate how Linux works."
--Eric Crampton
_______________________________________________
colorsync-users mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/colorsync-users
Do not post admin requests to the list. They will be ignored.