Re: Paper Print Resolution
Re: Paper Print Resolution
- Subject: Re: Paper Print Resolution
- From: Robert L Krawitz <email@hidden>
- Date: Tue, 17 Apr 2007 20:00:02 -0400
Date: Wed, 18 Apr 2007 01:48:09 +0200
From: "edmund ronald" <email@hidden>
Obviously you'd be in a position to know. That it happens at high
resolutions is plausible . Printing as a stochastic process :)
It depends upon the printer. Bidirectional printing on the Stylus
Photo EX yields horrible quality at any resolution. It isn't so bad
on the 870 and the like, but unidirectional still yields better
quality. The R2400 definitely yields better quality at *all*
resolutions in bidirectional mode, at least with my tests.
Naively, one would expect unidirectional printing to yield better
quality for at least three reasons:
1) The head position only needs to be calibrated at one endpoint; as
long as the head velocity is constant (or known), it doesn't matter
if the printer doesn't know the head position perfectly at the
other end.
2) If the printer can't compensate perfectly for acceleration and
deceleration of the head, the linear dimensions of the print will
differ close to the edges. If the acceleration and deceleration
rates aren't the same, bidirectional printing would cause
misalignment.
3) The head is not in contact with the paper. The ink has to travel a
short distance, in non-zero time, between the head and the paper.
In unidirectional mode, this travel distance (expressed as a
vector) is identical for all passes; in bidirectional mode, the
relative travel distance would be twice as great as the actual
travel distance.
Yet bidirectional printing is actually better than unidirectional
printing on the current generation of printers. Why? I don't know.
Some funky schtuff Epson has come up with, I guess.
On 4/18/07, Robert L Krawitz <email@hidden> wrote:
> Date: Wed, 18 Apr 2007 01:18:30 +0200
> From: "edmund ronald" <email@hidden>
>
> Historically, slightly less sharp. Quite possibly this piece of
> advice is, like the rest of me, skightly outdated :)
>
> My experience has been that on newer Epson printers bidirectional
> printing is actually *sharper* than unidirectional printing; in many
> cases, that's even true at extremely high resolutions (5760x2880).
>
> > Also, I have always used Bi-Directional printing (High Speed). I have
> > never ever been able to discern an iota of difference with it on or
> > off, although I never bothered to test this with my 4800s. This was
> > always the case with my other printers. I don't understand the
> > warning about using the High Speed setting. I am curious as to the
> > reasoning behind the warning.
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