Re: [Gimp-print-devel] Epson Stylus 660

[Thomas T. <tt...@bi...>]

Hrafnkell Eiriksson wrote:
> 
> Hi
> 
> I have just bought a Epson Stylus Color 660. I just installed
> v3.1.1 of the gimp-print plugin. I see that the Stylus 660
> is not listed in the setup for supported printers.

I have a Stylus Color 600. Haven't seen it print with the small dots the
UPD driver from Ghostscript uses. The 720 DPI modes work for the 600,
but the dots used are larger than what Ghostscript is using in the UPD
driver. We humble users can probably help here by doing a lot of
testing.

Even though the result from gimp-print is much much grainier (looks
indeed like 360 DPI) the colors and tones look better than
Ghostscript-UPD's.

> PS: Is the patent situation with dithering algorithms complicated?

I found out that at least the 'void-and-cluster ordered dithering
method' has been patented. Strange, because ordered dither (which is
done at the printer side) has been done for ages, and the ordered dither
that is used is not a mechanism, but a pre-generated data set. And that
would be copyrighted, not patented. And because the initial data set is
random, almost all of these would turn out to be unique. But in any
case: just using the void-and-cluster method gives results that are too
coarse for ink jet printing.

It might be worthwhile to try the few matrices that are on my website (
http://people.a2000.nl/ztonino/dither/files/64C for example) as the
randomizing data in the FS process. It is bound to be less visible than
true random noise. If the patent problems are too complicated for a
production environment, I'm willing to spend a day or more on an
"artistically created" equivalent. The good thing about void-and-cluster
generated random data is that it is of higher frequency than normal
random data: blue noise as opposed to white noise.


Thomas Tonino